Then I agree.

If you go down that path all discourse becomes meaningless. How could we discusses anything, or make sense of anything, if we radically doubted the veracity of our memories? — Janus

Fascinating. I hope you are right about this. Could you tell me, what is it about doubting the veracity of memory that entails that all discussion (thought?) is meaningless?

This is not correct. "4" must necessarily refer to one unit. Each of the numerals, "2", "3", etc., refer to individual units. If "4" referred to four distinct units we would not be able to carry out the mathematical proceedings which we do. For instance, 4x1 would be 1x1x1x1x1 if "4" referred to four distinct units. Instead, "4" must refer to one unity, a unity with the value of four individuals. — Metaphysician Undercover

Note first that I didn't say that "4" refers to four distinct units. I said that 4 means four distinct units. It is usual to recognize a distinction between the intension of a word - what it is that I have in mind when I use the word - and the extension of the word - the thing or set of things that the word is used as a label for. Take the concepts of "having a heart" and "having a kidney". Everything that has a heart has a kidney and so the extension of the concepts is the same. But the intension of the words is clearly different, since what I have in mind when I say "I have a heart" is different from what I have in mind when I say "I have a kidney".

For all I know, it might be that the extension of "4" must be one unity with the value of 4. Or, to put it differently, it might be that "4" is the name of a platonic form, FOUR. That doesn't change the fact that when I say "4", what I have in mind is four distinct individuals. Literally, what I picture when I picture "4" is four distinct units.

Now, you say that if the intension of "4" were four distinct units, it would follow that 4x1 is 1x1x1x1 and you say this is objectionable. That just sounds like you don't understand what multiplication is. The intension of "4" is

I I I I

and we are saying that we want this many units, once. If we said 4x2, we would be saying we want this many units, twice:

I I I I I I I I

Hence I don't see the issue.

There must be some kind of strange process going on behind the scenes. I am not following what is popular, apparently. Certainly not Wittgenstein's train of thought. — Magnus Anderson

I don't follow it either. He is enormously popular, but whenever I have interacted with an advocate of his views, they have begun by advocating something apparently novel, controversial and interesting and then after persistent questioning, it is revealed that they are really saying something trivial and uninteresting in some very pompous language - "language game" being one such example.

Am I right to understand that what makes 2+2=4 dubitable is that although I might decide the meanings of "2" and "4" such that it is indubitable, its still possible that any time I entertain 2+2=4 I am misremembering my own meanings of "2" and "4"?

That's exactly the same as saying "but, assuming that the future mimics the past, I cannot imagine the existence of zombies". — Magnus Anderson

Not really, since the meaning of "2" and "4" is something I can stipulate. I can stipulate that by "2" I mean:

I I

and by "4" I mean:

I I I I

What about this is dubitable? Can I doubt that "2" means what I think it does? Surely not, since I have decided what "2" means. What about this can I doubt then?

I am inclined to say that I cannot really doubt that 2+2 = 4. What I mean, specifically, is that I cannot imagine any way in which 2+2 does not equal 4. Sure, I can imagine that "4" does not mean the following number of distinct units:

I I I I

I can imagine that "4", in my language, means this many distinct units:

I I I

And I can imagine that, if that were true, 2+2 = 4, assuming that "2", in my language, means this many distinct units:

I I

I can also doubt that "2" means that many distinct units. But, holding the meaning of the symbols fixed, I cannot imagine that 2+2 is not 4. I cannot imagine that putting these units:

I I

with these units:

I I

would give me anything other than these units:

I I I I

Thus, there is a sense in which I couldn't really doubt that 2+2=4.

Best,
PA

So the idealist has to include the possibility that not looking will result in no longer experiencing, for no reason at all, since there is no unperceived death event. — Marchesk

We already agreed that the Idealist can posit (a) a car hurtling towards him when he sees it, and (b) a car hitting him in the back when he feels it. He need not postulate a car which exists in the interim, when he is not seeing or feeling a car at all, nor need he postulate that these three are 'the same' car. But, if he holds that (a) is usually followed by (b) - even if you look away - then why can't he hold (c) being hit in the back by a car will probably kill me? Would he be holding (c) for no reason at all? Surely not, unless for some reason the Idealist isn't allowed to think that bodily damage can kill him.

Best
PA

If the paper in your drawer no longer exists unperceived, then the piano falling toward you no longer exists when you look away.

So you should be fine as long as you don't look back. Same with crossing a street. Long as you can keep yourself distracted with headphones and only looking straight ahead, there shouldn't be any issue. — Marchesk

Your argument is that if Idealism were true and I saw a car coming towards me, I could stop myself getting hit just by looking away, since the car only exists when perceived. Idealism need not have that consequence.

It could be that it is just a brute fact that usually the experience of a car hurtling towards you is followed by the experience of a car striking you in the back if you look away. The Idealist can posit the two items experienced - the car that you see and the car that hits you- and say that usually seeing one is followed by feeling the other. He need not posit the existence of a car that exists in between these two states, nor need he say that all three are "the same" car.

The same with the piano. The Idealist says that there is the piano that you see falling towards you, and there is the piano that strikes you in the head, but he need not postulate another piano which exists when you aren't perceiving it, nor that all three are "the same" piano. Moreover, he will say, there is no reliable means at all, to tell that there is a car or piano which existed when unperceived.

Thought experiments are used in philosophy. — Marchesk

I know that they are, and for the most part I think they shouldn't be.

And this one can be performed in the real world. But you can change it a situation where there was a fire but nobody was aware of it, because they were asleep or it was in another part of the building, and they suffocated.

Similar to leaving the car running in the garage with you in it. — Marchesk

These examples can be explained as above.

Someone slips an odorless, tasteless poison into your drink when nobody else is looking. They leave the room.

Now the poison should ceased to exist just like the paper, right? You drink from the chalice and next thing you know you're vomiting blood and being rushed to the emergency room where the doctor figures out what poison was used and counters it to save your life.

So somehow that unperceived poison came back into existence. — Marchesk

I can perceive the drink. Am I perceiving the poison when I perceive the drink? The poison is part of the liquid isn't it? So surely I am. So why would the poison cease to exist according to Idealism? It wouldn't. I'm not perceiving the poisonous chemical constitution of the drink, but I can infer that chemical constitution from the effects that the drink has on me. I still don't see the issue. I am not saying that you can only know about things that you can see. I am saying that you can only know what you have a reliable ground to believe. I allow that you could know something by inference.

No, the idea that the existence of some unperceived object is a reasonable explanation for present experience's being the way it is depends on a prior acceptance of the world being pretty much as we think it is, with people who give you information, etc. — gurugeorge

Why can't I argue like does above, pointing out that if the car didn't exist when unperceived, I could save myself by simply looking away? Since I can't, we might conclude that the car must exist unperceived. As I pointed out to him/her, the Idealist can modify his view to accommodate these consequences. But could Marchesk not criticize the Idealist view then for being ad hoc, less explanatory and (in some sense which would need explication) less parsimonious? A number of people have hinted at this argument. I am trying to get someone to state it more fully. In what sense is Idealism less explanatory? In what sense less ad hoc? In what sense less parsimonious? I think these questions will prove difficult to answer, but if they could be answered, I don't see why doing so would assume anything like "the world being pretty much as we think". It depends what exactly I would have to assume, and why it is that I can't assume it. But you haven't said on either front.

Best,
PA

Although there are no immediate visual or audible cues as to gravity's disappearance, the occupants will nevertheless be instantly filled with alarm, as they are suddenly struck by that stomach-in-throat, I just jumped off the diving platform, feeling. They will perceive the disappearance viscerally. — andrewk

But this feeling that the diver has is one which he has as a result of falling. The idea of falling obviously assumes that there is somewhere to fall to, and that would assume that there is somewhere that exists while unperceived by the train passengers.

IOW, you ditch inference, and with it, explanations of any sort that aren't strictly deductive. You just have one experience following another for no rhyme or reason. — Marchesk

Indeed. Is there something wrong with that theory. What is it?

Then a partition is put between you and the fire that blocks your from seeing, hearing or smelling the fire. It ceases to exist as a perception. Furthermore, there is a timer that will let you out before your run out of air, but only if the fire on the other side of the partition is no longer consuming air.

What happens? Do you survive or does your air run out? How would Stace answer that? — Marchesk

Presumably he would say: First there is me and the experience of the room and the fire. Then there is just me and the experience of the room. The fire no longer exists since it is no longer perceived. After some time I cease having experiences and die. If I were told that there is this timer in the room which will let me free only if the fire doesn't exist, and I observe until the point where it is pretty clear that the timer is not going to let me out, perhaps I could infer that the fire still exists while unperceived. But I am not sure of the point of this thought experiment, because it is so contrived. If the experiment had been performed in reality, which it hasn't, that might prove the existence of the fire in those contrived circumstances, but the existence of regular objects in regular circumstances would remain unproven.

And really, why would the question of needing air come up at all? Why would you die of needing something (oxygen) you can't perceive? — Marchesk

I can feel the oxygen as I inhale it, can I not? If you say "no. You cannot tell from inhaling that what you inhale is oxygen molecules", then fair enough, but the existence of the molecules can be securely inferred from the perceptible properties of air.

You are being misled by your slideshow treatment of the world. It would indeed be strange if, when the paper ceased to exist, there were just this weird black space, as though the universe is literally a canvas and the piece of paper was literally rubbed out leaving a gap in the line work. But that wouldn't be what the Idealist imagines to happen. When he says that the paper ceases to exist when no one perceives it, what he imagines to happen is that the space where the paper was is replaced with empty space - not some strange erased nothingness, just ordinary empty space. Except, this wouldn't be quite right, since the Idealist holds that nothing exists when unperceived, and so he would have to maintain that the empty space inside the drawer doesn't exist either. But again, he need not be committed to this strange picture of the inside of the drawer being literally erased. He can maintain that the limits of existence are the limits of perception. Where perception stops, there is nothing. No empty space. No strange erased spaces with borders. Nothing.

I think a whole generation of philosophers, and an increasing number of those considering themselves scientists, would question in what way verifiable testing produces truths that are categorically more rigorous from truths detemined through other discourses, such as philosophical. — Joshs

Great point.

So I see the paper, right? But it's not that simple. What if I glance in the direction of the paper but don't process it as a piece of paper. We do that all the time. Our minds are preoccupied with other thoughts and we look right through something, not identifying it conceptually as 'this object'. And the act of identifying the paper as a thing is a protracted process. At first our visual system will process edges and then move on to a more encompassing recognition of the object. And our intentions and presuppositions enter into the perception in complex ways. — Joshs

Now, if instead of a human perceiving thepaper, we take a snake, the perceptual mapping of the works will look quite different, since perception is about interacting with an environment adaptively in relation to one's needs, rather than representing, mirroring or copying something. The idea of object would be, to say the least , wry different for a snake, if in fact a sense of persisting thing was necessary at all for it.
We could demonstrate how different the perceptual mapping of a world would be if we used a human infant, also, one who had not yet established object permanency, and for whom a piece of paper would likely not exist as a coherent object yet. — Joshs

It should be stressed that these two facts are about perception construed very differently. Animals perceive the world differently to humans in the sense that what they literally see - what is given to their conscious awareness - is different because they have different sense organs. Humans don't see the world differently in that sense. What humans literally see is for the most part the same or incredibly similar. What is different is their interpretation of what they see, in accord with their beliefs desires and needs. It is true that infants don't interpret what they see as a 'piece of paper' which exists permanently. But it isn't true that the infants don't literally see the paper. If they didn't see it, there would be nothing for them to later interpret when they pick up the relevant concepts. Its also true that usually I don't pay attention to every object which is part of my visual field. There is a television in the background of my visual field right now which has gone unnoticed by me for about half an hour. But what is all of this supposed to show?

what exactly would be appearing and disappearing in our world as our attentive processing shifted from moment to moment would not only be relative person to person, or creature to creature, or developmental stage to developmental stage, but also moment to moment. — Joshs

This seems to me a fallacious inference. As I said, it is true that people interpret the world differently, but it doesn't follow from this that what exists is person relative. This mistake is perhaps masked by your conflation between the given and interpretation of the given. If there really were nothing given at all, it would seem to follow that humans could only know about their own interpretations of the world, and never about an independent world. And from that one might conclude, ala Richard Rorty, that the idea of 'the word' independent of interpretation is a useless fiction. But as I pointed out, this would rest on confusing the given and the interpretation of the given.

Some difficulties are raised by the fact that different things are given for different creatures. That might put pressure on the idea that humans can know what the world is like in itself, and not just as it is for humans. But this is the point of a scientific account of things. In a scientific account, one is supposed to move beyond the features of a thing which are merely relative to human modes of perception, and seek a more objective characterization of the thing which explains why it appears a certain way to humans. Whether this really works seems to fall outside of the scope of what I wanted to discuss in the thread.

I suppose you would object to the idea of the given on the grounds that it is an 'impoverished abstraction':

Classical logic would say these are peripheral and irrelevant issues to defining the paper as physical entity, but classical logic is content tomsubstitute an impoverished abstraction for the more fundamental interactively determined meanings of how we interact with a world. — Joshs

As I see it, the idea of the given is that it is supposed to be an abstraction. In framing the notion of the given, we are trying to characterize perceptual experience solely by reference to the element which is common across all of us. We abstract away all of the person relative elements and call them the 'interpretation of' the given. What we are left with is the common element of experience, which is to serve as a reliable guide to the nature of the objective world.

Thanks for this, it got me thinking in an interesting direction.

I agree with you. I am only suggesting that the word 'know' needs further explication before the question is well-defined enough for a rigorous answer. Otherwise, the question admits of too many different interpretations. I think Kant failed to see this, but as did many before and after him.

"How can I alone, out of my own resources, know that things exist unperceived?" - then there is no answer, and I am led inevitably to solipsism. — gurugeorge

There is no reliable way for me to know that things exist unperceived at all? But I thought you said:

the hypothesis that the unperceived object exists, is a reasonable explanation for present experience's being the way it is. — gurugeorge

This argument sounds like an argument I could make using my own resources, doesn't it? And what about what other people tell me? Why can't what other people tell me count as part of my resources?

I suppose you might think that this would require that I first know, out of my own resources, that other people exist. That would be right, but couldn't I know this out of my own resources? If I couldn't, what sense does it make for me to enjoy the company of anyone else, given that it is mere guess work whether or not there is anyone else? This last paragraph is only speculation on what you might be thinking. Forgive me if I have gone off on the wrong tracks.

, you employ the same tactic sometimes employed by Marchesk. That is, to answer my question by asking other questions in the hope that my original question then sounds ridiculous. But your raising these questions does not answer my original question, so far as I can tell. It doesn't follow from the facts that (a) the paper is there when I look at T1 and (b) it is there when I look at T3, that it was there when I wasn't looking at T2.

Thanks again for the replies,
PA

What is pathological about desiring one's theories to be stable and lasting - immune from future upheaval? What is awful about what Descartes does?

Because it's there when you reenter the room and open the desk. — Marchesk

It does not follow from the fact that the paper is there every time I look, that it is there when I am not looking.

you can set a camera to record a video or snapshots of the paper while you're away. — Marchesk

This demonstrates the existence of the paper when recorded - recording really just being a sort of extension of our perceptual abilities. What about when the paper isn't being recorded? I surely believe that it exists whilst being unrecorded and unperceived. But how can I know it? Hence, the camera suggestion does not really help (I failed to realize this in a previous thread, and the discussion became confused as a result).

If you look up at the sky, is the ground still holding you up? — Marchesk

I can feel the ground under my feet so there is no problem here.

How far do you want to take the skepticism? Because it can go all the way to the current perception for me right now, and leave everything else as unknowable. — Marchesk

I want to take the scepticism this far and no further: any belief of mine for which there is no reliable method of establishing it, is one I shall doubt. I stress, as I did in the OP, that I am not demanding certainty or that all beliefs be capable of proof to any reasonable person. I am merely requiring that there me some method which is such that, when used correctly, produces beliefs which are more likely than not true. I don't think this is taking scepticism too far at all. To expect anything less is to believe things which are not even probable - guess work.

Let's say that when nobody is observing the rest of the universe, all that matter is destroyed. So you get in a car while nobody is doing astronomy, and the driver steps on the brakes. What happens? Do you feel the rest of the universe opposing your change in motion, or just the Earth and Sun and maybe Venus if it's up? — Marchesk

I see what you are saying, but I think there are problems. When the driver steps on the breaks, what I observe is the car slowly coming to a stop. I do not feel 'the rest of the universe opposing my change in motion'. Maybe there is no 'rest of the universe' at that moment. I realize that a scientific account of what happens when the driver presses his breaks obviously requires the existence of a significant part of the universe, but does that account prove that things exist unperceived or does it merely assume it? The account would need to be fleshed out further before I could say.

Here's another related way to go about this. Has anyone died from something unperceived? Yes, quite often. One example would be going on a hike and being killed by a falling rock. The hiker may not have seen or heard the rock. — Marchesk

The example isn't fleshed out in enough detail for a fair assessment. The hiker didn't see the rock, but did any body else see it? If so, then the example is compatible with things only existing when perceived. If nobody saw the rock hit the hiker, not even the hiker (perhaps he was asleep), then how can anybody say with any degree of reliability that the rock actually did hit him? This hasn't been explained.

Another would be dying from some disease, particularly in the past or places without access to medical equipment. You get sick and die from something nobody perceives. How does that work if the microbes, cancer, etc. doesn't exist? — Marchesk

What killed me are the microbes, and ex hypothesi, nobody perceived the microbes while they were killing me. Again then, how can anybody say with any degree of reliability that the microbes did kill me? It seems to me that typically this would be explained by a classic kind of causal inference. We perceive the person suffering various symptoms. We perceive the existence of microbes which we did not perceive before they got sick. We also perceive that as the symptoms worsen the number of microbes (for example) increases and their spread throughout the bodies crucial organs grows wider. We might infer that the best explanation is that the microbes do something to cause the symptoms and the eventual death. This can be further supported by other observations of the microbes behaviour on isolated tissue, and so on. In short, the microbes are observed to exist at certain times in conjunction with certain symptoms and in a certain patterns. When the symptoms are perceived on a different occasion, it is inferred that the microbes are again there.

But now return to the paper in my desk. How could this argument be run for that paper? I am hopeful, but not sure. Your further questions about digestion and intestines are the same. Does digestion happen when no one is perceiving it? Perhaps an argument like that I gave for microbes could be given. Although I'm not sure exactly how it would go. I made the thread hoping someone would explain how the argument would go, not simply restate my question with different examples!

By observing their actions such as dogs reacting to higher frequency whistles or homing pigeons. — Rich

That is, obviously, when you are observing them, not when you are not observing them.

However, if they stoped existing, everything would necessarily change since you are literally taking something out of existence. — Daniel

I don't understand why this has to be the case. Isn't it conceivable that you exist just as you now do exist without the existence of a collection of atoms completely distinct from you? It might be true that scientifically speaking, to remove certain atoms from the world all together would cause a change in everything else (though I am not sure about this), but that presupposes the whole atomic theory and causation, and both of these presuppose that things exist when unperceived.

You probably won't know, because of the crudity of human sensory organs, but in theory you could, in the same way as we know about a black hole: by its interaction with other things. A paper sheet in another room interacts with the desk drawer containing it, which interacts with the desk, which interacts with the floor and air, which interact with the walls of the closed room, which interact with the air outside the room, which interacts with you,

There would be tiny differences in the patterns of air movement around you if that piece of paper were not in that closed desk in the closed room. Your naked senses may not be enough to measure that but, at least in theory, if you had sensitive enough measuring equipment, you could detect the difference.

This is writ large in Wayfarer's / Russell's / GE Moore's example here (↪Wayfarer). If the train wheels ceased to exist once nobody was looking at them, the passengers would hear and feel an almighty jolt as the carriages they were in suddenly dropped onto their axles.

This response may not work for astronomical objects outside the observable universe, because of the expansion of the universe. But that's a somewhat different discussion. — andrewk

Thanks for the interesting answer.

Let us use the train example because having it writ large is a little easier. You say that if the wheels ceased to exist when unperceived, the carriages would drop onto the axles and the passengers would feel this. But this answer assumes that gravity continues to operate while unperceived does it not? W.T Stace first pointed this out in connection with a fire. Does a fire continue to burn even when no one is looking? A critic of Stace had said that it must do so, because when you return to the fire after ten minutes, the wood has turned to ash, which is just what happens if you stay and watch the fire burn out. Stace pointed out that this argument assumes that the law of causation operates continuously through time, whether observed or unobserved, and this is obviously part of what needs to be proven. The same can be said, seemingly, of the train example. That the carriages would fall onto their axles if the wheels didn't exist while unobserved assumes that the law of gravity continues to operate when unobserved, and this is part of what has to be proven.

This said, I suspect that there is a mistake in Stace's reasoning here - and so also with my reuse of it, but I don't know what it is.

Thanks to everyone for thorough replies

I'd also like to thank specifically, because I didn't address any of his/her points directly. This isn't because I don't appreciate the posts. Quite the opposite, I find them very insightful and the links provided equally informative. I do disagree with you Wayfarer, if you think, as it seems you do, that the view that the train wheels stop existing when no one is observing them is a silly view which only someone who misunderstands the issue - like you say Moore does - would discuss. I think this matter is not as clear as that, as I have tried to explain. I recommend W.T Stace's Refutation of Realism. Stace defends the view that 'nothing exists except minds and their perceptions', where this is taken quite literally and has the consequence that the train wheels do not exist when unperceived.

As to your suggestion that Kantian Idealism is about 'how we know what we know', the question depends on the word 'know' which is intolerably vague, and so it is hard to assess how Kantian Idealism is an answer to that question without an explication of 'know'.

Best,
PA

What do you mean by "actually given in perception"? How could this be different than what people in general consider to be given in perception? — Janus

There must be a distinction between what I think is given in perception and what is actually given in perception, just as there is a distinction between what I think is on the menu at Sizzler and what is on the menu at Sizzler. What is actually given in perception is what you actually see. What is 'there' before your conscious awareness. What I think is given may be utterly different.

Still, I think we might agree. I say that perceiving a hand is sufficient to end a regress of sceptical questions. You say that the ostensive definition 'this is a hand' is sufficient. I am not sure the two views are really different.

Cartesian doubt has always struck me as a kind of hilarious false drama, as if a drama queen were to write philosophy. — StreetlightX

Descartes' announces the aim of his doubts in the opening lines of the Meditations, and so I find it incredible that people have so often failed to understand his purposes. To me, he is perfectly clear. He was trying to find something 'stable and lasting'. He wanted to give an argument for some of his opinions - an argument so strong that it couldn't later be over turned. It isn't clear to me that this necessarily meant solving the regress problem or engaging in some sort of false drama. If you want to give a great advantage to your own philosophical theories over others, and you have just seen the fall of the most respected system so far (from Descartes' perspective) - the Aristotelean one - then what he tries to do makes perfect sense.

Best,
PA

Its true that I am what I am because everything else is not me. But it isn't true that nothing outside of me can change without me changing. In fact, this happens all of the time. When someone in India dies, do I - a person in the UK - change? Surely not. But then, it will not follow that if the paper ceased to exist I would change.

You'd have to be assuming that because otherwise there's no reason to suggest they do not exist when not perceived. If we know an object, O, exists when perceived, we know it at least existed. If you question its persistence sans-perception, the only way that can be the case is if perception causes existence. I don't see how you're not assuming that; it's the only possible way for the contrary to be true (unless things just happen randomly, I suppose). — MindForged

If 'assuming' means, 'assuming that it is true', then I am not doing that. We know that O exists at the moment, M1, when we are perceiving it because we are perceiving it at M1. But what about a moment, M2, when it is not perceived? Does O exist then? Here is a hypothesis which is completely compatible with what I perceive at M1:

(H) O does not exist at M2.

Nothing about what I perceive at M1 entails that H is false. You insist that I must be assuming that something is true. You say:

the only way that can be the case is if perception causes existence. I don't see how you're not assuming that; it's the only possible way for the contrary to be true (unless things just happen randomly, I suppose). — MindForged

I am not assuming that perception causes existence. For all I have said, it might be that when I perceive O, God instantly causes O to exist and when I look away, God destroys O. I am not saying this is true. I am saying it is compatible with everything that I perceive when I perceive O. It might also be that when I perceive O, some how this act of perceiving causes O to exist. I am not saying this is true. I am saying it is compatible with everything that I perceive when I perceive O.

We justified believing "O" exists by our perception, we didn't justify the notion that "O" exists only when we perceived it. — MindForged

This isn't accurate. By perception, you can establish that O exists at the time at which you are perceiving it. You cannot establish merely by perceiving O at moment M1 that O exists at M2 when you aren't perceiving it. That O exists at M2 when you aren't looking just isn't part of what you can see at M1.

there seems to be no grounds from which to raise the idea that the object stops existing when unperceived. — MindForged

What about the hypothesis that God causes O to exist and when I look away, God destroys O? What about the hypothesis that it is a law of nature that whenever we look in a certain place, O is created, and whenever we look away, O is destroyed? I am not assuming that either of these are true. I am saying that they are compatible with everything you perceive when you perceive O, and you have given no account as to how they can be reliably rejected.

Best,
PA

Perceiving them gives evidence that the objects at least existed at that time. — MindForged

Yes it does.

But does it therefore mean that not perceiving them lends justification to the idea that they don't exist otherwise? — MindForged

No it doesn't, and I would never make this inference. That is, the fact that an object, O, exists when perceived by me does not entail that O does not exist when unperceived. The former does not even make it likely that O does not exist when unperceived. So, I am not assuming that 'perception brings a thing into existence'. I am not assuming the opposite either.

But even given this, there is still a further question about whether O exists unperceived or not. Either it does or it doesn't, and the fact that it exists when perceived doesn't entail that it also exists unperceived. It might be, for all we have said so far, that O exists when I perceive it but the moment I stop perceiving it, it ceases to exist. I am not assuming that this is true, and so I am not 'idly speculating'. What I am saying is that this has not been ruled out by anything we have said so far. You have not suggested any reliable method by which we could determine whether something exists when unperceived. You have suggested that some things exist while they are being perceived, and I have agreed with you on that. You then seem to think that somehow it just follows that they exist when unperceived as well. It does not follow, unless there is some reliable way to establish that these things don't just disappear from the world when unperceived.

Is it 'idle speculation' to insist that we reliably establish the things that we believe? As opposed to simply accepting things with no basis. If so, then I suppose I am an idle speculator.

Best,
PA

During one's life, one is always perceiving new things as one develops skills in perception. — Rich

This is compatible with everything ceasing to exist when no one is perceiving it, so how does this support the view that things exist unperceived?

Other life forms are reacting to things we do not perceive. — Rich

How can this be known? How do you know that there are other life forms when you are not perceiving them?

Well I can raise a question about any old thing I want. Perhaps mathematical truths are only true when a conscious being considers their truth value. But as with your "simple question", unless there is a reason to motivate considering the question as being true or at least plausible, it seems like idle speculation. And that you seem to accept that objects exist when perceive would entail some kind of relationship between existence and perception if we wish to raise a question about if they exist unperceived. — MindForged

The first thing to note is that questions aren't true or false, plausible or implausible. Only propositions are, as I've always understood the words 'true' and 'plausible'. Second, the question I raise is hardly ridiculous. Is there any reliable way to tell that things exist when unperceived? If there isn't, then the belief that things exist unperceived is sheer guess work. The question itself isn't the idle speculation. Rather, a failure to answer the question shows that the belief in unperceived existence is idle speculation.

Lastly, yes, I agree that some objects exist when perceived. Hold up a piece of paper in front of your face. There is something that exists at the moment when you are perceiving it. But that doesn't settle the question of whether it exists unperceived.

The fact that you exist necessarily implies that everything that is outside you exists since it is something that is not you, and hence it is. The same applies to everything that you can perceive. That is, the fact that a paper sheet exists, which you are able to prove through your sense-perception, implies that everything outside the limits of the paper sheet exists, for what is outside the paper sheet is not the paper sheet, and thus it is. — Daniel

Agreed.

Therefore, even if you stop perceiving the paper sheet, what is not the paper sheet, ie. you and everything else that is not you or the paper sheet, by existing, causes the paper sheet to maintain its state of existence, for the paper sheet can only be that, a paper sheet. If it were the case that as soon as you stoped perceiving an object it would stop existing or it would exist in some other way, the change in the state of existence of the object would necessarily cause a change in your state of existence and in the state of existence of everything you are now perceiving. However, because this is not the case, it is same to assume that the contrary is what is real. Let me know what you think. — Daniel

Consider the paper case again. I hold a piece of paper in front of my face. At this moment, as I am perceiving it, it exists. Now suppose that I put the paper in a drawer and leave the room. Does the paper exist now? Why couldn't the paper cease to exist the very moment that I close the drawer and can no longer see it? You say that this would cause a change in me and what I am currently perceiving. Why would it? When I close the drawer I go into another room and am now looking at a bed. Why would things be any different if the paper ceased to exist when I stopped looking than if it continued to exist in the drawer. It seems that regardless of whether the paper exists or not, I will be perceiving a bed.

Best,
PA

Perhaps parsimony? — Michael

Maybe. But there is more than one type of parsimony, and it isn't clear that the view that some things exist when unperceived is more parsimonious in every sense than the view that things disappear when we aren't looking.

Its even less clear that a more parsimonious explanation is more likely to be true than a complex one. Although, I'd certainly take a great interest in any detailed statement of this argument from parsimony.

would be would it matter? Or is it just a matter of intellectual interest? — Michael

Well it matters to me since it is something that I believe, and I don't want to believe anything that I have no reliable means of determining. Ultimately, what matters and what doesn't depends on what we care to discuss.

Is there something out there in the fabric of the universe? Probably yes.

But what is it until Mind perceives it? That is the question. — Rich

Is there anything at all when the mind isn't perceiving? That is the question I am asking. If your answer is 'probably yes', why do you say that?

If that is the case, to give any reason to believe they do not exist when unperceived, don't you need to establish some causal relation between perception on one hand, and existence (or at least persistence) on the other? Otherwise it just looks like an arbitrary speculation. — MindForged

But I never attempted to prove that things don't exist unperceived, so I don't need to establish any causal relation between perception and existence. I asked whether there is any way that I can know that things do exist when unperceived. I haven't speculated at all. Simply raised a question.

Best,
PA

Because you haven't given a reason to motivate believing existence or persistence is dependent upon perception. — MindForged

So? Lacking a reason to think that Not-P is not a reliable means of establishing that P. It isn't a reliable method of establishing anything.

Does knowledge require certainty or just (strong) justification? If the former then you might not be able to know. — Michael

I explained what I meant by 'knowledge' in the OP.I don't mean to require certainty or justification. I only require that, whatever the method is that we use to determine whether or not things exist unperceived, the method be reliable.

perhaps it's more reasonable to believe that if things are found where they're left then they were there all along than to believe that they "pop" into and out of existence when you look. — Michael

Why is it more reasonable to believe that things exist unperceived than that they pop into existence? What is better about the former belief?

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PA

I am not particularly concerned about black holes or dark matter here. In front of me at the moment is a piece of paper. How do I know that this piece of paper still exists when I put it away in my desk and leave the room?

If he insists that it is worth doubting that two and two is four, that tells us again about Magnus, not about arithmetic. — Banno

What does it tell you about him?

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PA

Constitutive rules just are what a culture, a way of life, takes to be inherently given in perception, in life. Obviously this is mediated, but not totally determined by, individual cultures. Hands are the example in question. Since the hand is indispensable, in fact absolutely foundational, to all forms of human life and culture, whether prime-itive, ancient, medieval, modern, post-modern, creative or scientific; the fact that we have hands could not be more constitutive. — Janus

I assumed you were working with the definition of 'Constitutive Rule' given earlier in the thread, according to which a Constitutive Rule is an ostensive definition of a word. But here you say that a constitutive rule is 'what a culture takes to be inherently given in perception'. Is it what is actually given in perception, or merely what some people 'take' to be given?

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PA

because I can see it. — Janus

And this means that constitutive rules don't stop the regress. Sense perception does.

You cannot genuinely (coherently and consistently) doubt that there are any 'thises' at all because to do so would undermine the coherence of all and any discourse. — Janus

Sticking with our sheep example, I need not doubt that there are any things at all in order to make my point. I need only ask, in the specific case in which you are saying "this is a sheep", why you believe there is anything there at all. I needn't ask why you believe there are any 'thises' period. I can simply ask why, in this specific case, you believe that there is something there for you to name? If I can even raise that question, the regress goes on.

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PA

Sorry about this. Forgot to tag.

Let me stick with your sheep example and press on it. We find an animal and we decide to call it 'sheep'. I agree it makes no sense now to ask what justification I have for believing that the animal is a sheep and not something else. This is not the issue I am trying to bring out. The issue is that when I say to myself 'I shall call this a "sheep"', I am assuming that I have found something. I am assuming that there is some state of affairs for me to describe. The sceptic will ask, inevitably, why believe you have found anything? Why believe that there is anything for you to name at all?

The obvious answer is that we have sense perception. I can see that there is something there to be named. But if this has to be offered in answer to the sceptic, then constitutive rules don't stop the regress.

I am not asking how we determine which words to attach to which circumstances. I am telling you the following fact:

(a) There are certain circumstances, A, in which we stipulate that it is correct to say 'this is a hand'.

This is perfectly unproblematic, and I agree that we first undergo the circumstance and then stipulate the words that go with it. But, whenever I say 'this is a hand', I am blatantly assuming that I am in circumstance A (the circumstance in which we stipulated 'this is a hand' correctly applies). What justification is there for believing that I am in circumstance A?

You know the kind of circumstance A is: the kind in which I apparently see a hand, or have a sensory experience as of a hand, or however you want to put it. But why believe that I am in circumstance A?

Perhaps it is simpler to focus on the following question:

What justification is there for believing that I am in any particular circumstance whatsoever, as opposed to any other?

Best,
PA

Hi ,

The trouble with the account you propose is that Constitutive Rules are supposed to be regress stoppers. Suppose I say "whatever is going on right now, the correct thing to say is 'this is a hand', and anyone who doubts this must be not understanding how I use the word 'hand'". Now note that it isn't accurate to say that, no matter what is going on, the correct thing to say is 'this is a hand'. Rather, there is a very specific set of circumstances in which it is correct to say 'this is a hand'. Anyone who takes the regress seriously is going to ask why you believe that those specific circumstances have actually obtained. We can grant that if certain circumstances obtain, the correct thing to say is 'this is a hand', but we can still question whether those circumstances have in fact obtained. The idea that 'this is a hand' is a constitutive rule of the 'game' does nothing to prevent this question and so doesn't stop the regress.

Another way to put the point which is a little quicker is this. The idea that in this particular circumstance the correct thing to say is 'this is a hand', blatantly presupposes knowledge that I am in some particular circumstance and not another, and this needs justification.

Best,
PA

Suppose then that I suspend judgement about whether this is a hand. More exactly, I doubt that there is a this at all. I suspend judgement on whether or not there is anything that I am looking at. What is wrong with this doubt? I think in some sense you want to say that I can't do what I say that I am doing. But why can't I?

You first said that belief and doubt "would not be possible" without the constitutive rules. But now you say that belief and doubt "would not make sense". What is meant, exactly, by "make sense"?

That our hands are there (when they are) would seem to be, or more aptly, be an exemplification of, a "constitutive rule", in the sense of being part of the 'background' of implicit understanding without which no belief or doubt would be possible. — Janus

I must not understand what is meant here, because if I take the words in the way I find natural, what you say is obviously not true. "No belief or doubt would be possible" without these things you call constitutive rules. So unless I believe that this is a hand, then it isn't possible for me to believe anything at all? That sounds obviously false, since I might believe that this is a hallucination of a hand, generated by an evil demon. Or even more clearly, I might just not believe that this is a hand, whilst I do believe that this other thing is a foot. The other claim is that unless I believe that this is a hand, it isn't possible for me to doubt anything. But again, it seems plain that I might not believe that this is a hand, and I might also doubt that God exists, or doubt that man walked on the moon, or doubt that Smith killed Jones, or what have you.

So I am not sure what you could mean by 'no belief or doubt would be possible', unless you mean this obviously false thesis.

Best,
PA

Hi

Thanks for the detailed criticism. I agree with all of the background remarks.

The first premise of the Plantingan argument is:

(3) It is possible that a maximally great being exists.

Say that a maximally excellent being is one that is omniscient, omnipotent and morally good, like Plantinga does. We can then say that (3) is equivalent to:

(3*) It is possible that it is necessary that a maximally excellent being exists.

You rightly point out that the argument seeks to use the S5 model and so (3*) is really just tantamount to:

(3!) It is necessary that a maximally excellent being exists.

Thus, from (3), it follows that (3!). This just is the whole argument really; that God's existence follows from the logical possibility of his existence.

Your objection is that the argument trades on an ambiguity in the premise. Either the premise is:

(1) God exists as a matter of necessity,
or
(2) It is at least logically coherent to think of God as a necessary being.

You say that (1) obviously entails the desired conclusion, but as you point out, it is worthless because (1) just is the conclusion. So we have to understand the premise as (2). I am not sure what would be wrong with (2). You have said it is too weak, but I'm not sure why. Perhaps if I spell out my thinking directly, you could show me:

(2*) The concept of a being that necessarily exists is logically coherent.
(4) Therefore, it is logically possible that there is a being that necessarily exists.
(5) Therefore, there is a being that necessarily exists.

The inference from (4) to (5) is just collapsing the modal operators in accord with S5. The inference from (2*) to (4) assumes that if a concept is logically coherent, it is logically possible that it is instantiated.

Best
PA

Belief needs justification. So does doubt. — Banno

What do you mean doubt needs 'justification'? What counts as a 'justification' for doubting something? Could you give an example?

You might say, "well! Those are all bad arguments for doing anything. Sure, those are bad arguments, but people are flawed and bad arguments are good enough. — Bitter Crank

That is exactly what I would say. I agree that in a sense, IF you believe that the Jews possess all of those negative qualities, and IF you believe that it would be worth killing them all to get rid of these qualities, then it is rational to kill all of the Jews. But the fact is that it isn't rational to believe any of those things and so, all things considered, it isn't rational to kill all of the Jews. To say that Rationality itself is flawed because sometimes people do things which are, all things considered, irrational is like saying that a cooking knife is flawed because some times people use them to stab other people.

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PA

What possible criterion is there for judging whether something is really "there" or not other than that we can all see it? — Janus

I agree, but to say this is to say something very different to saying that propositions like "this is a hand" are constitutive rules which need no justification.

What do we make of someone who doubts that this is a hand? They have not understood the game.

There is a way of understanding "This is a hand" that is not explained in yet more propositions - "this is this". Understanding is shown by behaving in a way that agrees that this is a hand. The sceptic has not understood how to use the word "hand". — Banno

I am not sure how to assess this, since you didn't answer any of my questions. You say that if someone doubts that 'this is a hand', they have not understood how we are using the word hand. What if someone doubts that there is anything there at all? What if someone doubts that there is a 'this' to which you are referring? Doesn't your constitutive rule suggestion then fail to stop the regress?

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PA

the premise that he asks us to accept is much stronger than the conclusion of the argument. Thus, even those who already believe the conclusion independently may not accept his starting premise. — SophistiCat

The starting premise is that it is logically possible that a maximally great being exists. If someone believes that a maximally great being does exist, then they surely also believe that it is logically possible. Now consider someone who doesn't already believe the conclusion. Such a person might believe that the concept of a maximally great being is coherent. I think many people who deny the existence of God do believe that the concept is at least coherent. But then, it could be pointed out to them that this premise, which they believe, entails that a maximally great being exists. Why wouldn't that be an effective argument? I agree that most people always view the argument with suspicion when hearing it, but I think that is due to (1) the fact that people always view proofs of God's existence with suspicion, and (2) the Ontological argument is a priori, and people are always suspicious of a priori arguments.

I hope I explained why this is not the reason that neither I nor anyone who understands the argument that Plantinga is making - not in retrospect, but right as it is unfolding - would be likely to accept it. — SophistiCat

I am not sure you did explain that, or perhaps I missed it. Perhaps your thought is that once you see that the premise entails that God exists, you won't accept the conclusion. But isn't it true that every deductive argument is such that the premises entail the conclusion? If so, what exactly is wrong with the Ontological argument that makes it unpersuasive?

It is what StreetlightX and @Michael (and, no doubt, others who have criticized Anselm's argument) have said about predicating existence (necessary existence, as has been discussed, has even more severe problems). Having properties implies existence. So when we predicate a property of something, the qualification "provided that the thing exists" is already implied. When we define a unicorn as "a horse with a single horn," the same definition could be equivalently restated as "a being, such that if it exists, it exists as a horse with a single horn." The actual predicate here is still "being a horse with a single horn," nothing more. So when we "predicate" existence of a being, that is equivalent to saying "a being, such that if it exists, it exists" - which is just a tautology that applies to any hypothetical being. — SophistiCat

But this argument does not work against predicating necessary existence. I agree that the definition of unicorn as "a horse with a single horn" could equally be stated "a being, such that if it exists, it exists as a horse with a single horn". I also agree that when predicating existence of a being, it is like saying "a being such that if it exists, it exists", and this is to say nothing at all. But predicating necessary existence isn't a tautology and doesn't apply to any hypothetical being. Predicating necessary existence would be saying "a being such that if it exists, necessarily exists".

That, too. Plantinga's argument is, if anything, even easier to parody than the original. Those attributes of Super-Dupeness Maximal Greatness do no work in the argument - they ride free and thus can be replaced with anything whatsoever. — SophistiCat

I agree.

I don't think you're picturing every possible world. Surely you can imagine that one of these spheres doesn't share this thing in common? I certainly can. — Michael

I am sure you are right about that. I am only imagining at most five or six worlds. And not only do I think I can imagine that one of these six spheres has nothing in common with the other five, I seem to be able to imagine sets of possible worlds where no member of the set has any objects in common with any other member. But if the concept of necessary existence really makes sense, then I really can't do this, since all of the worlds must contain the necessarily existent thing. This is what I mean when I say that I can't imagine anything that is necessarily existent, and so I am not sure that I can really understand the concept at all.

I can imagine a possible world without a God, and so God can't be necessary. It's ridiculous to think that you can just define him to be, just as it would be ridiculous for me to define the Flying Spaghetti Monster as being necessary. This is the problem with treating "existence" as a property. — Michael

I think I can imagine a world without God, but what am I (you) really doing? I imagine some hills, trees and buildings. Perhaps I imagine a few people and an animal or two. I might imagine the earth as seen from space. The picture I paint doesn't have God in it, and so I conclude that I can imagine a possible world without God. But what I have imagined is at best a pathetically incomplete part of a possible world. 99% of the details about that world are left out, and all I have is a handful of images. Who knows, maybe if I did imagine the entirety of a possible world in all of its detail, I might discover that I can't coherently do so without including God. But then, maybe I discover that I can.

I am quite the sceptic about modal knowledge.

Best,
PA

Yes, I think that's exactly the issue which Sam26 brings up, the infinite regress of justification. One proposition justifies another, which justifies another, so on and so forth. Hinge-props are proposed as a means to put an end to this infinite regress, by being beyond reasonable doubt without needing to be justified. This is supposed to ground certainty.

My argument is that because hinge-props are outside "the game" of epistemology, and are therefore not subject to justification, they are actually the most dubious. — Metaphysician Undercover

Thanks for the clarification. It depends what is meant by saying "this counts as a hand". As I said, if it is an ostensive definition of "hand" then I don't find it problematic at all. One can simply stipulate that by "hand", one means, this. Is such an ostensive definition a dubious proposition? In one sense I don't think a definition can be dubious. If I choose, for my purposes, to use the word 'hand' as a name for this, what is there to doubt? One might ask, 'why call this a hand and not some other name?', but this is a semantic, and not a substantive, question. The simple answer is 'I've decided on this name. You can use another name if you like. It doesn't really matter'.

But, as I said in my last post, even if acceptable, this is largely useless, since the sceptic will want to know why you believe that there is a this to be called 'hand' at all, which means the regress hasn't been halted.

Best,
PA

I can't see how rationality leads to evil deeds, even some times. Name one evil deed which was the result of rational thought? I know some people have claimed that they have perfectly good reasons for mass murder, or human trafficking or what have you, but the reasons they have are always poor arguments. So it isn't then Rationality that is flawed, it is an evil man with poor arguments that is flawed.

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PA

How can a necessary thing exist in one possible world but not the actual world?

I can't quite put my finger on the actual logical misstep. There's something wrong about talking about the logical possibility of the logical necessary. I wonder if such talk requires something like Tarski's hierarchy of language, or different sets of possible worlds, and the argument above conflates the members of the hierarchy/conflates the sets.

It just isn't right to say that there must be a necessary thing because a necessary thing is defined as something that exists in every possible world (and so the actual world).

As I said, the only thing that could perhaps be said to exist in every possible world is "the world", which is just an abstract container. — Michael

It isn't that a necessary thing must exist because a necessary thing is defined as something which exists in every possible world. Rather, if the concept of necessary existence is coherent, there must be a necessarily existent thing, since coherence entails logical possibility. If there is something wrong here, my suggestion is that it is the concept of necessary existence. I could not prove that it is incoherent, but it does seem like a very strange concept - a thing which cannot fail to exist. Any logically coherent story of how things might be must contain this thing. Either the world of Harry Potter contains this thing or the entire story is incoherent. Either the world of Sherlock Holmes contains this thing or the entire story is incoherent. Either Lord of the Rings contains this thing or the entire story is incoherent. I suppose what is really strange about it is that any object which I can imagine is such that I can apparently give a perfectly coherent description of a world without that object. I cannot really imagine anything to have the property of necessary existence, and so I wonder, do I really understand that concept at all?

Sure, I can use possible world lingo to make it seem less obscure. "Imagine a being which exists in not just one possible world, but every possible world". I then picture all of these different spheres and the necessary thing is in not just one, but all of them. That's what necessary existence is, I tell myself. But its just a metaphor, and the fact remains that I can't imagine it at all in a particular concrete case. Nothing I can imagine is such that I can't also apparently imagine it not existing.

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PA

Hi

Constitutive rules can be written as "X counts as Y"

So "a diagonal move of any length counts as a move for a bishop in chess".

"Here is a hand" can be read as constitutive in that it is setting out what counts as a hand.

How would "the human being consists of body and soul" be written as a constitutive rule?

"A human being counts as a body and a soul" or "A body and a soul counts as a human being"?

DO they work? Perhaps. — Banno

Interesting reply. So a constitutive rule is a proposition which takes a certain form. You would read 'here is a hand' as 'this counts as a hand'. Well, what is meant by 'hand' in this phrase? If all that is meant by 'hand' is this (where I am pointing to my hand), then the proposition reads 'this counts as this', which is just an uninteresting tautology. It might be right that that proposition is exempt from any request for evidence because it is already self-evident, but what is the significance of this seeming triviality?

Alternatively, is "this counts as a hand" just an ostensive definition of "hand"? If so, I agree that it is exempt from a request for evidence. But what I don't see, is how this solves the regress problem (I assume this is what it is meant to do, since that was the problem mentioned in the OP. Forgive my not having read the entire thread). Or rather, I don't see how it can solve that problem in a way that is different to what Descartes did - and I assume it is meant to be different. If we are trying to put an end to the regress of justification by saying "this counts as a hand", won't a sceptic simply say "what is the justification for believing that there is anything there at all? Why do you think there is a this?". A Cartesian will say that he is immediately acquainted with this; that it is given to him in consciousness in such a way that he cannot be mistaken that there is a this before him. We could then add 'this counts as a hand' as an ostensive definition, but this is clearly parasitic on the Cartesian answer, and inherits all of the problems of that answer. Perhaps I am putting Cartesian words in a mouth that doesn't want them, but how else can we answer "Why do you think there is a this?"?

Best
PA

So the ontological argument doesn't defend its assumption that the necessary thing (assuming there is one) has those other properties posited of God. — Michael

I think you are right about this. While the assumption is defended by defining God as 'the most perfect being', this defence is objectionable on the grounds that what is and is not perfect is entirely subjective and context dependant. If this is right, then the argument can at best show that there must be something which necessarily exists. But what is it? Who knows.

(2) If it's logically possible that a necessary thing exists then a necessary thing exists — Michael

Although saying that, I find 2 troublesome. To be logically possible is to exist in a possible world and to be necessary is to exist in every possible world, and so the second premise states that if a thing which exists in every possible world exists in a possible world then a thing which exists in every possible world exists. It defines a necessary thing into existence. — Michael

I am not sure that 2 'defines a necessary thing into existence' if this is meant to be a bad thing. If a necessary being exists in one possible world (it need not be the actual one. Suppose it isn't), then it must exist in every possible world, including the actual world. The point of 2 is that, from the assumption that a necessarily existent being is logically possible, it follows that a necessarily existent being exists. It doesn't define anything into existence. You might accept 2 and deny that a necessarily existent being is even logically possible, and thereby avoid the conclusion.


All of this is quite uncharitable to Plantinga.

First he asks us to accept that a Super-Duper Being is at least within the realm of the possible (not his exact words, of course, but that doesn't matter, since he doesn't explain what the words mean in this premise). Hopefully, a charitable and careless reader will not ask what a Super-Duper Being is and will grant this premise for the sake of an argument. — SophistiCat

He does define his 'super-duper being' very carefully. He defines a maximally great being as one which is maximally excellent in every possible world, and maximal excellence is defined as entailing omnipotence, omniscience and moral perfection. To wit, the first two premises of his argument from the Nature of Necessity, page 214:

" (34) The property has maximal greatness entails the property has maximal excellence in every possible world.
(35) Maximal excellence entails omniscience, omnipotence, and moral perfection. "

You are right that he asks us to accept that it is possible:

"(36) Maximal greatness is possibly exemplified. "

He doesn't explain what 'possibly' means in these passages, but it is uncharitable to say that he 'springs the trap' revealing that 'possible' was being used in the technical sense of modal logic. The argument is discussed in detail in The Nature of Necessity, which is a book entirely about the possible and the necessary, in the technical sense of modal logic. So when he comes to discuss the Ontological Argument, he takes it that people who have read him thus far will know that he is still using the words in the same way he was using them throughout the book. Hardly a sprung trap.

Of course, stated this way, no one who does not independently believe the conclusion would go along with such an argument (and those who do ought not go along with it either). — SophistiCat

This is a criticism which Plantinga himself makes of the argument, and he makes it in the Nature of Necessity. Nonetheless, I think he should not have made it, because its a poor criticism which rests on ambiguity. It is true that if I look at the argument, and I am utterly convinced that God does not exist, then I won't grant Plantinga's 36, once I see that 36 entails God's existence. Obviously I will reject it. But that's just a fact about my bias, not a reflection of the worth of the Ontological Argument. If I am utterly convinced that the earth is flat, then even if you show me a photograph of the earth from space, if I understand that this being a photograph of earth entails that the earth is not flat, I will deny that it is really a photograph of earth. And again, that's a reflection of my own bias, not of the worth of the argument against flat earth.

But then, suppose I don't have this bias. Suppose that I am not such that, when I see that a premise entails that God exists, I will not accept that premise. Suppose I don't believe that God exists but if I were shown that God's existence follows from something that I do believe, I would accept it. Suppose I also believe that the concept of God is perfectly coherent. Plantinga might point out to me that the coherence of the concept entails the logical possibility of God's existence, and then further point out that the logical possibility of God's existence entails his actual existence. Wouldn't that be convincing for such a person?

You also say that it is illegitimate to predicate necessary existence. Why? You say that Michael's argument shows why. But which argument of Michael's do you mean? Do you mean the argument that we can tack 'necessary existence' onto any concept and then create an argument for its existence, regardless of what the concept is?

Best
PA

The Ontological Argument is given a bad time in this thread. I think a study of the Ontological Argument has taught us more about logic than almost any other philosophical argument. Its certainly a very fruitful piece of Philosophy in that sense.

There are many versions of it, some intensely complicated. The OPs version is Anselmian, and those arguments typically run:

(1) If God exists then God necessarily exists. (G -> nG) [Partial Definition of God]
(2) If its logically possible that God exists then God exists (pG -> G) [From (1)]
(3) It is logically possible that God exists. (pG) [Premise]
(C) God exists (G) [From 1-3].

The first premise is supposed to be part of the definition of God. God is, by definition, an absolutely perfect being. He is omnipotent, omniscient, wholly good, eternal and if he exists, exists necessarily. I do myself wonder whether the notion of 'perfection' isn't merely subjective, and so cramming all of these properties into one definition is a little arbitrary. Still, I don't think this undercuts the argument in any serious way.

The second supposedly follows from (1), given that p(nX) -> nX (if its possible that X necessarily exists then X necessarily exists). I don't deny that this is controversial, but I've yet to see anyone argue against it in this thread.

The third premise claims that God's existence is logically possible. I don't think I have ever seen a 'proof' of this. But many people do in fact believe it, even people who are Atheists might be inclined to think that God's existence is at least logically possible. The argument would then be of some value, even if it couldn't prove God's existence to someone who doubted (3). Proofs don't have to be proofs to everyone no matter how sceptical, in order to be valuable, do they? At any rate, all one can do to illustrate logical possibility is try to explicate the concept clearly and carefully, remove confusions and reply to anyone who argues that it is incoherent.

Let me take a closer look at some of the objections in this thread.

All the argument can show - all every such ontological argument can show - is that if God existed, the argument would hold true. — StreetlightX

Every 'ontological argument for God' engages in this slight of hand: beginning with a material conditional and then silently dropping it along the way. — StreetlightX

I do not believe that the material conditional is silently dropped away in this reconstruction. The point can be made in possible world lingo, for illustrative purpose. If God exists at all then he exists in every possible world. From this, it follows that If God exists in at least one possible world then he exists in all of them. If we assume that God exists in some possible world, it follows that God exists. I stress that the possible world lingo is only illustrative. One shouldn't be lead to think that 'possible worlds' are some how real and the proponent of the argument is assuming God to exist somewhere off in some far away land! In any case, I don't see the masked 'if' which you describe.

There exists a being, such that, it exists.
Therefore, it exists. — StreetlightX

I stress again that the first premise is that If God exists then he necessarily exists. There is room to 'escape' the argument by denying (3).

Or,

Imagine a being, such that it cannot fail to exist.
Therefore, it exists.

(That's Plantinga's version, only he obfuscates it a bit.) — SophistiCat

You see I don't think so. None of the premises of the argument say 'imagine a being such that it cannot fail to exist'. The first premise defines God as necessarily existing if existing at all. It doesn't say that God necessarily exists. The second premise is entailed by the first (yes, given axiom S5 in modal logic). The 3rd premise merely says that its logically possible that God exists. So I cannot see that the argument I have sketched (which is Plantinga's, just simplified) amounts to the bad argument that you give here.

We imagine this thing to be all-powerful, all-knowing, all-good, and real. If it isn't real then we can imagine something greater that is imagined to be all-powerful, all-knowing, all-good, and ... really real? The argument doesn't make any sense. — Michael

For the argument to work, we must imagine something that if it did exist, would exist in every possible world (or necessarily). If you imagine something that, if it exists, exists merely in one possible world, or five possible worlds, or even 9000 possible worlds, but not the actual world, then you have not imagined an absolutely perfect being, have you?

Here is what Kant said, that existence is not a real predicate or property of a concept. — bloodninja

Indeed, and Kant was right. But necessary existence is a property, and is immune to the criticism which Kant makes. It really does add something to the description of a thing to say that it necessarily exists, rather than just exists.

Best,
PA

No, because it is not a constitutive rule. — Banno

I've always found the idea of hinge-propositions difficult. I share some of 's doubts but let me ask some different questions.

Supposedly, hinge propositions do not need to be supported by any non-question begging reasons because they 'operate outside of the game'. They are something like the rules of the game, and you make the analogy with the rules of a game of chess. You include G.E Moore's 'here is a hand' as a hinge-proposition and you deny that Dualism is a hinge-proposition. What is the game that 'here is a hand' is a rule for?

Further, you say Dualism can't be a hinge-proposition because it isn't a 'constitutive rule'. Well, doesn't it depend which game you are playing what the constitutive rules are? 'Knights move in L shapes' is a constitutive rule of chess, but it isn't constitutive of Sid Meier's Civilization, where knights can move in any shape within a fixed range of tiles, and then there's Monopoly, which doesn't have knights. Why can't Dualism be a constitutive rule for some game or other? I suppose this is related to the fact that I'm not sure what game 'Here is a hand' is a rule for, or what is meant by 'constitutive rule'.

Best,
PA.