You've argued that science does not progress through abduction, which is a fair point, but that doesn't imply abduction is not truth directed. — Relativist

Science doesn't progress solely via abduction, but it certainly could not progress at all, or even get off the ground, without it.

You are putting a lot of theories in my mouth. I am not trying to defend what Kant said but clarify what I heard he was saying. Neither was I trying to defend what Aristotle said.

I am guessing that Kant introducing a new standpoint is neither here nor there from your standpoint. — Paine

I didn't mean to suggest you were defending Kant. Perhaps I should have been more careful with the wording.

I think Kant did introduce a new standpoint, and I also think doing that is always worthwhile in moving ideas along. Kant's standpoint seems to me to be superceded today.

That our judgement is, to some extent, a result of our nature established before our particular experiences is not, by itself, an observation given through experience. Kant calls that part thinking about what occurs "independent of all experience." — Paine

You mean that we are not born blank slates is not something we can know via our experience of ourselves? Can we not know via observations, both our own and via accessing the records of the observations of others, e.g., via ethology and anthropology, that we and other animals are not born as blank slates?

Also, referring to having a pre-cognitive nature as being a purely mental attribute seems tendentious. Physiological investigations seem to show that what is given pre-cognitively via the senses is processed by the body pre-cognitively, and only ends up being conscious experience on account of processes of which we have no awareness or knowledge in vivo. The understanding we do have of such things would seem to be all a posteriori.

Experience is prior in time to knowledge but the possibility for experience is prior as a condition.

In the sequel therefore we will understand by a priori cognitions not those that occur independently of this or that experience, but rather those that occur absolutely independently of all experience. — Paine

I'm afraid this makes no sense to me. I don't see how any cognition can be "absolutely independent of all experience". Can it be explained?

The need for the a priori is to explain why we are built that way. The need becomes necessary by the "altered method of our way of thinking." Otherwise:

If intuition has to conform
to the constitution of the objects, then I do not see how we can know anything of them a priori
— CPR, Bxvi

The analogy with Copernicus is to demonstrate how mutually exclusive the two standpoints are. — Paine

We don't know anything of objects or phenomena in general a priori—in terms of what commonalities we can know about all objects without actually consulting particular objects in real time, we must reflect on their general characteristics as perceived. That is we must reflect on prior experience of phenomena in order to see what they all have in common.

We have before us quite different notions of abduction. Sometimes it is talked of as the process of forming an hypothesis. We know that, for any set of observations, there are innumerable possible explanations. Simply having available a range of hypotheses is insufficient. We must choose between them. — Banno

There are not innumerable possible plausible explanations. It is not abduction that might inform as to which explanation is most plausible but induction, which really just consists in the (vast) network of empirical knowledge we already have in place.

Abduction is simply the business of imagining explanations in ways informed by current scientific understanding.

Well, we experience phenomena, and from that we inter noumena. The latter is not experienced, and the former isn't something not us. — noAxioms

Don't we experience the phenomena as being other than ourselves? Why bring noumena into it?

Indeed, and my reply was to reaffirm that the testing of an hypothesis is not part of performing an abduction. Abducting is choosing the "best" hypothesis, on the basis of one's preferences - the very meaning of confirmation bias - the tendency to interpret a situation so as to confirm one's preexisting attitudes. — Banno

I don't think it's fair to say that the hypotheses that are chosen are merely a matter of one's preferences—to repeat, they should be consistent with current scientific theory and understanding. If you want to call that confirmation bias, then you'd better apply that judgement to the whole of science.

Confirmation bias consists in ignoring evidence that tells against one's preferred beliefs, and scientific practice should be the opposite of that—it should involve actively trying to falsify current accepted belief and theory and attempting to find better, more comprehensive hypotheses.

I had a quick look at the SEP article, and I didn't find it helpful—firstly because I don't think there is a significant difference between the two kinds of abduction it [purports to identify, and secondly because it seems to conflate the process of imagining hypotheses with a purported tendency to believe in them.

As I understand it, abduction is simply the creative imagining of hypotheses—and the next step would be to test them rigorously—if someone doesn't want to do that, but wants to cling to their "per hypothesis" that has nothing to do with abduction per se. So, abduction is not confirmation bias in any necessary sense, although of course abductive reasoning might be used to confirm biases.

you really haven’t given a validation of abduction. — Banno

It doesn't need to be validated. What would you replace it with?

To put it concisely 'abduction" simply refers to the process of forming hypotheses.
— Janus
Well, if that is all it is, then it doesn't tell us which to choose among the many - which is "best"... — Banno

There is no certain way to ascertain which is "best". That's why I said "seems best'. The only way to ascertain whether a hypothesis is a good one is to test it, which means seeing whether the predictions that are entailed by the hypothesis are observed.

You mentioned parsimony, coherence, and predictive success—the first two would presumably be in mind when forming rigorous hypotheses. Coherence would be relative to consistency with existing accepted scientific understanding.

In any case, to refer to my original response—I was disagreeing with the assertion that abduction has anything to to with confirmation bias, and I say this is not so because hypotheses are to be tested, not accepted on account of their "feeling right" or whatever.

That said, feeling right might come into play in choosing between rival hypotheses, but acceptance of one over the other would be contingent on entailed predictions being observed, as well as coherence with current accepted scientific belief and understanding.

There's that word "best" again. It hides that the criteria being used are things such as parsimony, coherence, and predictive success, normative concerns. Why not drop the pretence of "abduction" as a seperate rational process and look instead at the basis that scientists use for choosing between rival theories. — Banno

I don't think you understand what 'abduction' means in the context of science. It is the use of the imagination to come up with what seems to be the most fitting explanatory hypotheses. Of course testing is a separate issue. I only used the word 'best' to underline the fact that in hypothesizing the desirable aim is always to come up with what, consistent with whatever criteria, seems to be the best explanation possible given whatever limits of information and imagination are in play.

Testing is an entirely separate issue—it comes after the hypothesizing. To put it concisely 'abduction" simply refers to the process of forming hypotheses.

Notice that testing is a seperate process to abduction - one adduces the "best" explanation and then tests it. Abduction is not necessary for testing an hypothesis. — Banno

As I say above I haven't said or implied that testing is a part of the abductive process. Of course abduction is not necessary for testing an hypothesis—it is necessary for coming up with an hypothesis to be tested.

Abduction is little more than an attempt to formalise confirmation bias. — Banno

Not at all. Abduction is the use of the creative imagination in formulating testable hypotheses that might best explain the observed facts. An abductive hypothesis is always provisional—open to rigorous testing, and thus quite the opposite of confirmation bias.

We use the past to predict the future because ...
... there is no other guide.
— Janus

The difference between us is that you call that rational, and I call it desperation. We are desperate to predict because we want security, and there is no security. Such is the fall into knowledge. — unenlightened

That seems a rather strange, if not perverse, response from someone who thinks we should be guided by the science as to what to do about human-induced global warming.

But what I have not seen in all this pragmatism is any answer to Hume. His claim is that one of our "background beliefs" seems to be that the future will be broadly the same as the past, and this is something we cannot have any evidence of whatsoever because the future is always beyond our experience. It is therefore plucked out of the total vacuum of unknowability and it is on this literally unreasonable assumption that all this "pragmatic rationality" is founded. — unenlightened

All the evidence we have points to the conclusion that the future will be broadly like the past. Hume was, in my view, merely pointing out that this is not a deductively certain conclusion. It is rational to take past experience as a guide to predicting what the future might be like, simply because there is no other guide.

It is not, to put it in Kantian terms, pure reason which is at work in this, but practical reason. Whether nature's apparent laws are truly necessary laws or merely acquired habits, it doesn't matter. Even if they are merely habits, it still takes a lot to change a habit, for us as well as nature. It is arguably more rational, in general although of course there are exceptions, to stick to our habits, provided they really are rational, that is well-considered, ones.

Overuse of resources, environmental pollution and habitat destruction do not count as rational well-considered habits, even though we may not be able to be deductively certain that they won't somehow magically renew themselves.

So it seems difficult to see how any system, if it experiences at all, can experience anything but itself. — noAxioms

Don't we also experience a world of things other than ourselves? Perhaps you mean something different—that we don't experience being other things?

Of course, but actually going through with one's personal salvation project used to be reserved for the select few, certainly it wasn't meant for everyone. — baker

To be free of the primary "cares" of the world involves renunciation, and not many are capable of, or want to do, that. Even with renunciation there is no guarantee of salvation or liberation. The whole desire for, and belief in, salvation could well be just a fear-based wishful delusion.

One problem with that is that the watered down versions are being promoted as the real thing, and can eventually even replace it. — baker

What you say assumes what is at issue—that there really is is a "real thing" to be found.

Of course. However, the striving for harmony usually involved a lot of torture and killing in the past, and still involves a lof of strife. — baker

Right, there is no perfect harmony. And what portion of humanity people consider to be their kin, or even their kind, is a big issue.

.Then they are making justification into something other than justification. Justification is per se persuasive. Persuasiveness isn't something that gets tacked onto justification. A false justification is something that purports to be persuasive but is not. The question of how we know whether a justification is adequate has to do with logic, inference, validity, etc., and goes back to what ↪I said about "the Aristotelian way to develop such an idea." — Leontiskos

To be persuaded is no guarantee of the soundness of what has done the persuading. I just don't see how the truths or falsities that constitute a purported justification for some belief can be irrelevant. You yourself say that a "false justification is something that purports to be persuasive but is not", which seems to agree with what I just said. Although the "purports to be persuasive" seems wrong, inapt since people are often persuaded by falsities. I would change the "persuasive" there to 'true'.

I think it's just an expression of one of the meanings of "knowledge." — frank

Yep, there are at least a few others.

The stability of H₂O, photons, electrons, or gravity is only meaningful within the systems of concepts, practices, and distinctions that we impose. — Tom Storm

Careful—you're starting to sound like @Wayfarer. That the stability is meaningful is not the same as to say that it exists. The conflation of meaning with being or existence is a constant in Wayfarerland. Of course things can be meaningful only to a percipient who finds them to be so, but it is certainly bad logic that concludes they can only exist in the human understanding. Why should we doubt that the patterns, regularities, forms and invariances we find everywhere in nature exist independently of us?

To say they don't seems to be the height, or better, the low, of human hubris , anthropomorphism, anthropocentrism and human exceptionalism. It also seems extremely implausible that we could construct these ourselves from scratch and fortuitously find that the predictions based on understanding them can be so successfully used to navigate the world.

:up: :lol:

OK. Is there any activity that you see as a non-physical activity? Unless there is, you've deprived "physical activity" of its meaning. — Ludwig V

I'll be convinced of that when you can point to a non-physical activity. I say all activities involve energy, and I count energy as being physical.

If say I am certain that something is the case, then I mean that there cannot be any doubt about it. Then I would say I know it to be the case. If I think something is the case but there is any possible doubt it, then I would say that I believe it to be the case, but do not know it to be.
— Janus
There is a difference between the possibility something might not be the case and it actually not being the case. You are treating mere possibilities as if they were actual. — Ludwig V

I'm not treating mere possibilities as though they are actual at all. I've already said I have no truck with radical skepticism that is based on the mere logical possibility that I might be deceived. All I'm saying is that I will not claim to know something is the case if I see any possibility of its not being the case. Depending on how I gauge the likelihood of the possibility that it not be the case, I might nonetheless believe it to be the case—that is provisionally accept that is the case.

For example I will say I know I am typing at this computer, or that I see the towel on the line outside my window being moved by the breeze, because I see no possibility of reasonable doubt about those.

Why? Where does it say that it is not possible to know something but not to know that you know it? It isn't like a pain or a taste, where what I say determines the truth. I suspect that you are thinking of the first person "I know that I know..." But it is perfectly possible for me to say "Janus knows that p, though he thinks that he believes it." — Ludwig V

I'm not saying it is "said anywhere", but that the idea of knowing something yet not knowing that you know it makes no sense to me, except in cases where I may not recall that I knew something. Even there, can I be said to know something I previously knew if I can no longer recall knowing it? Knowing that you know something consists in being able to explain how you know it, in my view.

Can the justifications for thinking it true be themselves true even if the theory is false?
— Janus
Yes, if the justification is not conclusive - i.e. not sufficient. — Ludwig V

How do we ever know when the justifications are sufficient to warrant thinking something is true? That is the problem that leads me to think that if it is a matter of justification, then we are talking about belief, not knowledge. If I am certain I don't require justification.

I see why this is attractive. "Possible doubt" is the question, though. Is it possible that the sun will not rise tomorrow? — J

It is logically possible that the laws of nature might change and the Sun burns itself out in seconds rather than taking billions of years. But that is, if all our scientific understanding is correct, not physically possible. The alien race scenario may or may not be physically possible, but it seems so vanishingly unlikely that it would be perverse to take it as a reasonable doubt. So I would say that I do know the Sun will rise tomorrow because I cannot see any possibility of reasonable doubt that it will.

Right, and to restate my point, J's objection holds against any theory of knowledge which takes truth to be a necessary condition of knowledge, and this is not just JTB, it is pretty much every theory of knowledge. — Leontiskos

I am not sure about that implication of what @J has been arguing, but I think truth is a necessary condition of knowledge, and I also think knowing the truth and knowing how you know it is also a necessary condition of knowledge. That said, I am not claiming that we cannot think we have knowledge and yet be wrong.

As I have said in the past, I would want to use the words valid/invalid and sound/unsound for justifications, and true/false for propositions. That itself clears up part of your conundrum, albeit not all of it

Regarding Evolution, I think it is clear that the theory of Evolution is not knowledge in the strictest sense (scientia), and therefore it is not demonstrable. The theory of Evolution involves precisely the sort of probabilistic guesses that some take all knowledge to be bound up with. — Leontiskos

I take the ToE to be a way of understanding, like all scientific theories. We can say it differently and say theories are ways of knowing, but that is a different sense of knowing than "knowing that", or propositional knowledge. I would not say that we know the ToE (as opposed to evolution as such) to be wholly true, it may have parts that will be superceded, for example. One example of this is that the "central dogma" (that acquired characteristics cannot be inherited) has turned out to be thought to be not strictly true with the development of epigenetics.

Whereas "The sun will rise tomorrow" gets an enthusiastic thumbs-up from me as a piece of knowledge, despite the fact that it too is not certain -- there are defeaters, as I proposed to Janus (who wasn't impressed!). — J

I responded to this example of yours for the first time in this very post, so I'm not sure what you mean when you say I was "not impressed'. As you will see if you read the above I agree with you that I think it is reasonable to say we know the Sun will rise tomorrow.

Yeah but if the bar is that low you could make the case for any sort of ticket machine being a philosopher since it "Accepts or rejects some set of values or other".

The point is more to examine the things that you hold and why you hold those to be true, that's generally the core of philosophy in my experience. — Darkneos

The ticket machine cannot state that it has accepted or rejected values. The ability to state what is on one's mind would seem to be a minimum requirement for doing philosophy

I agree with you that an important part of philosophy consists in questioning one's assumptions and conclusions, but the rudiments of philosophy consist in having assumptions and reaching conclusions.

Yes, I've often aspired to this, philosophically speaking, anyway. But there are too many cute and counterintuitive ideas out there not to be at least half-interested in the subject. — Tom Storm

Oh, I agree—I'm interested in any and all speculative ideas, even though I take many, even most, of them with a grain of salt.

My prejudice is that unless someone has genius of some kind and can generate innovative theories without any special training (e.g., Wittgenstein), or unless they have some expertise that allows them to see the world differently, who cares what they think? — Tom Storm

I tend to agree with Hegel that the history of philosophy consist, for the most part, in "the same old stew, reheated", and I think any interesting new ideas in philosophy have always come on the back of science.

That was working not too bad before social media came along and pushed the consensus beyond a hierarchical balance and into dysfunctional polarisation. Two sides now only wanting to cancel each other out. — apokrisis

Yea, the problem of ideology and dogmatism, political or religious—the inevitable polemic—us and them. Even if you offer a rational critique of an ideology, you are automatically cast by the ideologue or the dogmatist as ignorant or vicious—as "one of them".

If civilisation and culture want values and meaning, do they really have to commit to idealism and its absolutism? Can't a sorry old pragmatist like me not have values and meaning without all the claptrap? Just living a productive life and enjoying it? — apokrisis

A salient question. My take is that we are better off without the idea of overarching values, because that leaves us with the freedom to create our own values. This is not to refer to the pragmatic values that are essential to community functioning, but to say that those values don't need to be presented as given by a transcendent/ divine lawgiver.

Yeah, I wasn't suggesting that everyone identifies themselves as a philosopher. Is anyone who identifies themselves as a philosopher a philosopher? Like anyone who identifies as an artist is an artist? They don't have to be good. There are good and bad philosophers just as there are good and bad artists.

What I was suggesting is that everyone has a propensity to extoll some set of values or other, and if philosophy is "love of wisdom", which amounts to "how best to live" or in other words ethics, then I think most people have some interest in that. Of course some might buy into the idea that the best way to live is not to give a fuck. I dislike the idea of 'philosophy as profession' in any case. I see philosophy as being one of the most basic characteristics of humanity. As Heidegger says "Dasein is the being for whom its being is an issue". (Roughly paraphrased because I couldn't be bothered to look it up).

I don't think everyone is a philosopher like he says, most people don't really seem to question the way things are in life and just go along with it with what they were taught. — Darkneos

I don't know, I guess it depends on interpretation. I think everyone is a philosopher in some sense insofar as they have accepted or rejected some set of values or other.

On the other hand, not everyone thinks for themselves, and I think this probably includes at least some professional philosophers. Does one need to be an original thinker to be counted as philosopher?

The "publish or perish" demand on academic philosophers has probably led to a plethora of mediocre works.

You can always start a thread dealing with a subject that interests you.

In conflating a false explanation with a true explanation, and inferring that someone who possesses the false explanation possesses the requisite justification. — Leontiskos

JTB declares that we possess knowledge when our justified beliefs are true. The problem, as I pointed out earlier, is that if we don't know whether the justifications for our beliefs are themselves true then where does that leave us? How do we know they are adequate as justifications?

Or looking ta it the other way around, take the Theory of Evolution, for example. It seems we are amply justified in thinking it is true, but we don't really know whether it is true. Can the justifications for thinking it true be themselves true even if the theory is false?

I think the core problem here is J's Humean "game of pool" epistemology. If every belief is reducible to a guess and the mind never merges with its object in reality in the way that Aristotle describes, then J's conclusion that truth and knowledge do not exist is foregone. All of this meandering and ignoratio elenchus is just a working out of that Humean presupposition. — Leontiskos

Hume was skeptical of what cannot be observed as "matter of fact". If I know you well, and I see you fall off your bicycle, there can be no doubt in that moment that I see you fall off your bicycle, so I can say that I know you fell off your bicycle because I saw it happen. How long does the "no doubt" situation last, though?

That would be down to the accuracy of my memory. I might say my memory is very good and has been well-tested over the years and hardly ever fails me, and even when it does only in small matters, not significant ones like you falling off your bike, but that doesn't logically entail that my memory remains reliable, or even that my memory of the results of my memory being tested is accurate.

But there have been tens of thousands, hundreds of thousands, millions of mutations that led to the multiplicity of life here on earth. Just saying “mutations” doesn’t really have much meaning. — T Clark

I was just saying that mutations might be counted as proximate or efficient causes of evolution, if evolution is change in organisms and mutations cause change in organisms. Efficient or proximate causes are thought to involve energy flows and exchanges—chemical reaction for example.

I don’t see it. How does the the full context of existence here on earth constitute its purpose? — T Clark

I don't think existence has an overarching purpose, but there are many purposes motivating various organisms. Whereas traditionally final cause was thought of in terms of purpose or telos, I am thinking of it in terms of function or place in the overall system. I'm thinking along the lines that every part has a place, a function, in relation to the whole, as well as being constrained by the whole, by the overall existing conditions.

Yes. But I reject the antecedent. We cognize many things that are not physical. Mathematics for a start. — Ludwig V

I see doing mathematics as a physical activity, involving pencil and paper, computer, or neural activity.

I don't know...perhaps you are misunderstanding me—I'm not talking at all about being cautious in trying to avoid false beliefs. but about avoiding thinking and saying that I know something if I cannot be certain about it.
— Janus
I take the point. But a lot depends on how you define certain. If you define it as something that's not possibly wrong, I would have to take issue with you. Something that is possible can possibly be actual and can possibly not be actual. So the strongest definition of certain is too strong. — Ludwig V

Perhaps we are speaking at cross-purposes. If say I am certain that something is the case, then I mean that there cannot be any doubt about it. Then I would say I know it to be the case. If I think something is the case but there is any possible doubt it, then I would say that I believe it to be the case, but do not know it to be.

In the first case, if someone pointed out that there was some real possibility of doubt, and convinced me of that, then I would say I had been mistaken in thinking that I knew whatever it was to be the case.

Maybe I'm confused. In general, I think that "S knows that S knows that p" is not ungrammatical, but is empty. The only kind of case that would give it some content is a situation in which S knows that p, but is confident that they know that p. (Someone who answers questions correctly and can justify their answer, but is hesitant, for example.) But their hesitation is not about whether they know, much less whether they know that they know; it is about whether p. — Ludwig V

Say I believed that something is the case, and for very good reason, despite thinking that there was some small possibility which could cast a doubt about it—then I would say I believed it, but did not know it, to be the case. Then say I found out that the small possibility of doubt had been unfounded—I would then say I now know it to be the case.

But if I had justifiably believed it to be the case previously, despite thinking there was a small possibility of doubt and the small possibility of doubt turned out to be a mistake, then according to JTB I would have already known it to be the case despite the fact that I didn't think I knew it to be the case. That would be knowing despite not knowing that you know. And that just seems weird to me.

Well, physicalism is a metaphysical position, so we could quibble that the label here is a bit biased. I see no reason why a strict empiricism should be positing anything like physicalism or "the physical," which would be metaphysical speculation. For instance, causes, of which "other minds" would simply be a special type, are a sort of additional metaphysical posit above and beyond regularities in experience. — Count Timothy von Icarus

I would say that everything cognizable via the senses as well as our bodies and the act of cognizing itself, if a neural activity, all count as physical. Causation may not be directly perceived, as Hume asserts, but causes and effects are always physical phenomena.

Descartes' skepticism is not about the real world. It's about whether my experiences are veridical. He's not saying that, if these experiences are not veridical, then there is no real world. He's saying we can be deceived. Presumably the Evil Demon can be undeceived, just as the Lords of the Matrix can be. — J

Surely skepticism about the veridicality of experiences just is skepticism about the external world? I'm not sure what you mean by saying the Evil Demon or the Lords of the Matrix can be undeceived.

What are the efficient causes of evolution? — T Clark

Mutations perhaps?

Some seem to consider overall conditions to be equivalent to final causation not efficient causation.
— Janus

I don’t get that. It’s certainly different than my understanding of final cause. — T Clark

The final cause was traditionally considered to be the telos or purpose of a thing. That would involve how it fits into the overall web. We can think of the global conditions, which include both constraints and opportunities, as providing for the possibility or impossibility of the existence of particulate things and kinds of things. Think of environmental niches, for example.

Yep, I guess it could be.

It is my understanding that an asteroid hitting earth about 65 million years ago caused the extinction of many species of animals, including the dinosaurs. If that hadn't happened, it is likely that humans never would have evolved. If that's true, did that asteroid impact cause our existence? — T Clark

There are efficient causes and then there are overall conditions. Perhaps the overall conditions for the evolution of humans would not have obtained if the asteroid had not hit. Some seem to consider overall conditions to be equivalent to final causation not efficient causation.

in fact in the case of metaphysics I would say there can be no certainty at all, that it all comes down to plausibility, because we are dealing with the non-cognitive.
— Janus
If metaphysics is about the non-cognitive (which needs a bit more fleshing out), are we sure that certainty and plausibility even apply? — Ludwig V

That's an interesting question. If everything we cognize is counted as "physical", then would not metaphysics, thought of being what is beyond the scope of physics, or any other science, be thus taken to be dealing with the non-cognitive?

Why do we need to talk in terms of 'knowledge that' when nothing is lost by talking instead of 'justifiably believing that'?
— Janus
Well, if there were something to be gained, it might be a change worth making. But so long as we distinguish between true beliefs and false ones, the issues remain. — Ludwig V

I want to note that I'm not saying we don't know anything—I'm saying that in those cases where we can be said to know something, we know (again, radical skepticism aside) that what we know is true. It seems to me if we do not know that, then it doesn't count as knowledge but as belief. It could be justified belief, and then it would that its truth is highly plausible, but that still falls short of knowing it is true.

It seems to me that your meteorite example with the conclusion that you should "take your cue from society" and ignore the mere possibility just counts as an example of a justified belief—you don't know that a meteorite is not going to strike you on the head, but you could be said to know that the chance of its happening is miniscule, so knowing that it is highly unlikely means that believing it would be to believe in an extremely implausible event.

If it is wrong to believe something that might not be the case, then, presumably, it is equally wrong not to believe something that is the case. The more cautious you are in avoiding false beliefs, the more you risk not accepting true beliefs. — Ludwig V

I don't know...perhaps you are misunderstanding me—I'm not talking at all about being cautious in trying to avoid false beliefs. but about avoiding thinking and saying that I know something if I cannot be certain about it.

We can only pretend something that is possible. So if something is possibly false and we can pretend to know it, then it must be possible to actually know it. — Ludwig V

I'm not certain what you are saying here, but the question that comes to mind is whether it is possible to know something without knowing that know it. The very idea just seems wrong to me. JTB does seem to make this possible, and for me that is to its detriment.

The Matrix Hypothesis I think is absurd, because it posits that there is a real world in which the virtual world we inhabit is sustained, and this means the need for explanation is just pushed one step further back.
— Janus

But Descartes' doubt isn't about explanation. He believes it's possible to doubt whether my experiences are veridical -- that is, of the things they appear to be of. He's not questioning experience in general. The Matrix hypothesis would represent such a doubt. — J

I'm not saying that Descartes considered the Matrix hypothesis at all—I don't think he did— because as I said I think the Evil Demon scenario is really very different, apart form the idea of being radically deceived in both scenarios.

In the Matrix scenario there is no skepticism about the real world—in fact that is what those who see through the virtual illusion are trying to get back to. If Descartes considered this he would still be faced with the question of being able to doubt the purported real world just as much as he can doubt the virtual world of the Matrix.

By introducing "explanation" I meant to refer to the question as to how we could be certain of the reality of anything. We can doubt the virtual world, but how can we be certain of the reality of the world within which the Matrix is sustained?

.

He wants the grand prize -- absolute certainty, beyond even the possibility of doubt. I personally feel that we don't need that in order to do metaphysics and epistemology; Descartes disagreed, hence his Method. But we really shouldn't see him as raising "philosophers' doubts" for the sake of skepticism. He detested skepticism and believed he had refuted it. (And we have a perfectly good modern version of the Evil Demon: the "Matrix hypothesis.") — J

I think absolute certainty is as impossible as radical doubt. You simply cannot doubt everything—some things need to be taken for granted in order to doubt. I agree with you that we don't need absolute certainty in order to pursue metaphysics and epistemology—in fact in the case of metaphysics I would say there can be no certainty at all, that it all comes down to plausibility, because we are dealing with the non-cognitive.

I wasn't saying Descartes raised doubts for the sake of skepticism. Quite the opposite—he was after a degree of certainty which I think is impossible. The Matrix Hypothesis I think is absurd, because it posits that there is a real world in which the virtual world we inhabit is sustained, and this means the need for explanation is just pushed one step further back.

The problem that I have with the idea of knowledge being defeasible is that if it isn't true it isn't knowledge, so if what I think I know is possibly false, then I don't really know it—so I say instead that I believe it and that it is belief, not knowledge, which is defeasible.
— Janus
I think one defeats a claim to knowledge if it is false. Possibly false is far too strong and leads to us abandoning swathes of what we know quite unnecessarily. "possible" does not imply "actual". — Ludwig V

I would say that it we determine that something is possibly false then we don't at all need to "abandon it" but merely to abandon the pretense that we know it to be so, for the more modest claim that we believe it to be so. Why do we need to talk in terms of 'knowledge that' when nothing is lost by talking instead of 'justifiably believing that'?

:lol: They're not real sunglasses and it's not a real sun in Matrixland.

OK, that seems like a good way to look at it, with perhaps the caveat that it's reasonable also to ask, "Why are you certain?" or "What makes you rely on this experience?" (similarity to previous ones, presumably). — J

Cheers, that's a fair question—and I hope I can answer it to your satisfaction. I take it that possession of knowledge obtains when there can be no doubt. For example, when I am looking at something there can be no doubt that I am looking at that thing. When I am doing something there can be no doubt that I am doing that thing. Same with feeling and thinking.

The problem that I have with the idea of knowledge being defeasible is that if it isn't true it isn't knowledge, so if what I think I know is possibly false, then I don't really know it—so I say instead that I believe it and that it is belief, not knowledge, which is defeasible.

As to Descartes, I understand his skepticism to be methodological—an attempt to determine what it is possible for him to doubt. The problem I have is that he doubts things on the mere logical possibility that he might be deceived by an Evil Demon. I think such doubt is absurd. I agree with Peirce:
"Let us not pretend to doubt in philosophy what we do not doubt in our hearts" .

Agreed. I think we're speaking of self-justification here. Can you justify to yourself that "I am thinking X" is necessarily true? — J

When I think X or feel a sensation, there can be no doubt about it. So, I see no need for justification. Justification is only for beliefs, not for those things known with certainty. (Note: I leave out of consideration the kind of radical skepticism that Descartes feigned, simply because I think it is always a matter of feigning.

Ah, the sound of intellectual impotence. It's uninteresting. It's unimportant. It's irrelevant. Why in the name of John Locke should I be concerned about what you find to be uninteresting? — frank

You don't have to find the same things I do uninteresting. In fact I didn't say those merely logic possibilities are uninteresting anyway, so you are putting words in my mouth. I said they are vacuous, meaning they possess no content which could inform us, so for the purposes of metaphysical speculation, they are best ignored (unless it can be shown that they yield any material that should be taken into consideration.

In fact it is you attempting to impose your values on me, with the slur "intellectual impotence" just because you think I don't find the same things interesting that you do. Why should I be concerned about what you find interesting, especially if you cannot demonstrate that it contains anything worth taking seriously because it is something the truth of which might actually be determined?

Still, it could be a collective dream. It really could be. We don't know. :grin: — frank

That's one of those vacuous merely logical possibilities that are best ignored, because even in the unlikely event that it were true (which we could never know) it would be a difference that makes no difference.

Kant’s point is that principles like “every change in velocity has a cause” are synthetic a priori: they enable prediction, but also hold necessarily for all possible experience. That’s what allows physics to be both law-governed and universally valid. — Wayfarer

We don't know if physics is law-governed and universally valid. It's universal validity is merely an assumption and the laws may have evolved as habit (pace Peirce). Same with causation―we can only explain changes in terms of causation, and it doesn't necessarily follow that all changes are caused. Imputing causation is an inveterate habit of thought―even some animals do it.

Firstly it is science that posits the existence of dark matter and energy on the basis of observations. So, they are considered to be a part of the Universe as understood by science.

You are now saying science is not a guide, but you said this earlier:

Therefore the guide must include evidence from the empirical sciences, but not be restricted to those principles, thereby employing a method which extends beyond them. — Metaphysician Undercover

If the guide includes evidence from the empirical sciences then the empirical sciences are guiding metaphysical speculation. Intuition is always itself guided by the current state of knowledge or scientific paradigm. Intuition in unconstrained speculative free play can come up with anything that isn't a logical contradiction, so by itself is not a reliable guide at all. I don't prefer referring to it as intuition anyway, but rather as imagination―creative imagination invents hypotheses designed to explain what is observed―it's known as abduction.