As far as I understand it - for Kant, the "thing in itself" is definitely not to be equated with God. However, I suppose there may be Kantians who might try to argue for such an identity. As I understand Kant, his suggestion is that you cannot reach any conclusions about God using theoretical reason because theoretical reason is confined to operate within the bounds of space and time, and whatever God might be, it is not constrained by space and time. This is also true of the thing in itself, for Kant, so I guess there is some motivation for trying to tie the two ideas together, but Kant never did so himself (as far as I'm aware). For Kant, God and religion and morality and so on become the domain not of theoretical reason but what he called "practical" reason, where the demand for intellectual rigour is a lot less strict, and you don't have to give proofs for what you believe.

How one should live? and if God exists? What's the relation?

Well, and this is definitely not Spinoza's position, if you thought you could prove that the Abrahamic God exists exactly as described in the Torah and New Testaments, then the answer to the question "How should one live?" would be answered by appealing to the laws handed down directly from that god to human beings via Moses. So that would be one possible link between the questions "Is there a God?" and "How should one live?". Spinoza had a different conception of what God was, but he seems to think also that certain ways of living are to be preferred over others because they align more with the nature of the God that he supposed he had proved the existence of. I cannot possibly do justice to Spinoza's Ethics in a mere philosophy forum, and ultimately you'll have to answer for yourself the question "What, if any, moral implications follow from particular metaphysical systems?"

If we see something blurred as opposed to clearly, or as you suggest through a filter of some kind, I admit there is a good deal of motivation - independently of any apriori convictions about materialism/idealism - for thinking that the difference is not in the "objects of vision" but rather the viewing equipment. So there is certainly something in what you say. However, in regards to afterimages, I'm not so sure that this motivation applies, or even if it does, that it trumps the "act-object" view of what is going on. After all, you mention that to get someone to see an afterimage we might ask them to look at the same wall they were looking at earlier, but now there is an overlay, okay - so what's "an overlay" other than an object of vision distinct from the wall? Adverbialism, as I understand it - and admittedly, I'm perhaps not being very charitable - is simply an attempt to brush overt commitments to such strange "mind-dependent" objects of vision under a carpet of language, in the hope that no-one tries to flatten out the bumps. I suppose the point I am advocating is that it fails phenomenologically, and because it fails phenomenologically, that gives us some evidence for supposing that it is false. Suppose, for instance, you track an afterimage across a room, on the analysis you are proposing, it would seem we would no longer be keeping an eye on one thing, it would have to be interpreted as seeing a lot of different things modified in similar ways, but splitting it up like that might in the end fail to do justice to the phenomenology of tracking.

Anyway, perhaps there is a more basic/general question to address before asking questions about afterimages specifically, and that is "what are the objects of vision?". Berkeley and others after him (realists and materialsits alike) took the basic building blocks of perceptual objects to be instances of visible properties - specifically colour and shape. If that is right, the question would be "when we see afterimages are there instances of visible properties that are objects of vision or not"? If there is an instance of redness when I see a red afterimage - regardless of the logical form we finally give to afterimage statements - then I think questions with consequences for realism / directness/indirectness of perception would still have to be answered about those instances.

Thanks, but no need to apologise, my question was probably a little too basic for this technical thread anyway, so I started another one specifically on adverbialism. As for Sellars and theories of truth, I can see a motivation for the idea that a theory of truth has at some point to find a place to deal with our language forms themselves, in addition to the non-linguistic world and any suppposed relations (e.g. 'correspondence') there may be between that world and the ways we have of expressing facts about it. However, I guess what interests me most is that with perception (which is where adverbialism applies) we (at least seem) to be as close as we can get to a non-linguistic contact with reality, and so perception might have a role to play also in deciding which forms of language should be preferred. Anyway, I've started up another thread on adverbialism to discuss that issue, and I'll leave this thread to discussing the deeper technical issues with predication.

I'm not sure why Spinoza chose the title "The Ethics" for his work, but it is above all a work of metaphysics. As far as I understand him, though, he believes that his metaphysical system actually entails ethical conclusions, and I think he was of the Socratic position that all philosophy was ultimately aimed at answering one question: how ought one to live?

Common sense is right about the feather and the iron ball, at least insofar as dropping them from the top of the tower of Pisa is concerned. Of course, if you could create a vacuum for them to fall in, common sense would be asphyxiated.

Physics subsumes common sense

- the original article I linked to actually argues (or rather points to other people's arguments) that physics undermines common sense, and then goes on to say that common sense rules, so physics has to be taken with a pinch of salt.

Thanks for this post, which I found enlightening. I'd often suspected that there was something circular in Dennett's position. Doesn't he try to dissolve the "problem" of the mind in nature by saying that it's simply a matter of taking an intentional stance in regard to the behaviour of certain animals, whereas we could (at least in principle) adopt a purely "machine" stance or "system" stance to that same behaviour? The circularity then comes in when you ask Dennett the question "What is it to take any kind of stance at all?" - which as far as I recall, he never raises himself, but perhaps someone on here knows different.

For attempts to argue for God's existence, you could do worse (at least in my opinion) that to read Descartes' Meditations (from memory the arguments for God's existence are in meditations 3 and 6 but you should read all 6 anyway - they are by no means as difficult and dense as Kant). Then move on to Berkeley's Three Dialogues Between Hylas and Philonous.for a different take. Spinoza presents a variation of the Ontological Argument in The Ethics. The first thing to get clear about though is what you are supposing the term "God" to stand for - it's pretty clear that Spinoza and Descartes had different things in mind.

"Well, it actually does matter if something is caused by a psychoactive substance or not."
Why? The question I'm interested in is the one ProcastinationTommorow clarified: do such mental phenomena provide counterexamples to theories of mind that require all mental phenomena to have objects? Is it that the investigation of the causes of the state will reveal that it actually has an object after all, despite its superficial "lack" of a target?

This may be off-topic to some extent, but is there a link here to the position in the philsophy of mind called adverbialism? From what I gather, the idea is that natural language leads us to think that statements such as "John saw a red afterimage" are to be treated relationally, linking two things, John and his afterimage, and then we start asking questions about what kind of curious things afterimages are. However, if we recast the statement (which is the move that adverbialists recommend) into the form: John senses redly, all we need in the world is John and his properties, and no strange afterimages. My problem with adverbialsim, and it may also have some bite against Sellars jumblese idea, is that even if you can recast the form of a statement in such a way, the question will always remain as to what makes the statement true, and if John senses redly is made true in the same way that "John sees a red afterimage" is made true, then we are still at liberty to think that the adverbialist's statements are made true by the existence of strange objects called afterimages. Do we need a theory of truth before we can decide if jumblese makes sense as an idea?

:up:

I agree the author of the article seems to be a bit of a crank (seems he or she thinks he or she can prove god exists for one thing). Having said that, I'm not sure I agree with your analysis of the argument concerned. As far as I understand the Principle of Least Action, at a general mathematical level it involves integration of differences between values over times, and requires that the integral be minimized. If a principle requires that some value be minimized, it allows that there might be all manner of possible values for that integral, and when applied to basic motion problems, those possible values do cash out as possible paths that particles or javelins or whatever might take. Thus the commitment to possibilia. The argument seems okay to me, at least structurally, although its individual premises might turn out to be untrue, or require other assumptions. For instance, I seem to recall reading that the Principle of Least Action can itself be deduced from Newton's Laws of Motion (which don't have ontological commitments to possiblia, just to instantaneous forces) so I guess there is a question of what laws or principles should be regarded as more basic. Of course, the Principle of Least Action is more general I presume, since as the cranky author says, its used in many different areas of physics.

but the epithet "reality" is not a halo

Isn't it? I would have thought physicists wouldn't be too happy to be told that when they talk about electrons etc that they are not talking about real things. It's not like they are writing novels is it?

Thanks Akanthinos and Ying for the explanations and pointers to further reading. Not that I'm taking any sides here - but what about this unfocussed anxiety of mine? Whether or not it be self-inflicted as a result of drinking too much, it's a mental phenomenon (I presume, although perhaps it depends on definitions of terms) but doesn't seem to have an object. Do any RTM or CTM philosophers ancient or modern talk about apparently objectless mental phenomena?

A mistake people are making about Descartes (it seems to me) in much of the discussion so far is that he took his cogito to be a deductive argument. We all know the expression "I think therefore I am" but that formulation is NOT the one to be found in the Second Meditation. There it is just stated "I am,exist" and is not (somewhat misleadingly) dressed up as a premise and conclusion. Descartes' point (whether you agree with him in the end or not) is that there are some propositions that do not require proof, they simply wear their truth on their sleeves, so to speak. His idea was that the entire edifice of science can then be constructed on the basis of those bedrock propositions (plus the rules of inference, of course). He may not be right about that, but he certainly wasn't wrong in the way some people on here seem to be suggesting.

Some of what this Cogitson is saying sounds like the kind of arguments Berkeley gave for his empirical idealism (you might already have read Three Dialogues Between Hylas and Philonous, but if you haven't, try just the first one - it's an easy read). The thing Cogitson needs to be careful about is that there is a difference between arguing that existence is mind-dependent - which is what the perceptual relativity arguments aim to show - and arguing that existence is an illusion (which given how Cogitson introduces his spiel, I guess is what he wants to prove). Cogitson and Berkeley aren't that far away from each other though, and Berkeley goes one better - he actually believed he was proving the existence of God by establishing the proof of empirical idealism.
Good luck with the book.

Not much of a philosophical argument. As for Corvus

If no one is looking at the Moon, the word ËXIST' has no meaning. Hence the Moon has no meaning either in that case.

, that's not much of an argument either, although at least it has a premise and a conclusion, even if it's not clear how they are related to each other. In any case, Corvus is right that the point isn't just about our moon, it's about existence in general, and whether things that are not actually being perceived exist or not. Occidental commonsense screams "of course they do", but what passes for commonsense in the West might not be true (I started another discussion on this point 'Commonsense versus physics').

Thanks apokrisis for the detailed reply. I have a couple of points/questions:
1:

Colour is a mental property ... somehow explained by electromagnetic radiation being a universal material state and brains

Isn't that precisely the kind of view that the author of the article is saying involves a contradiction?
2:

So the idea of fermions and bosons..is dissolving

Is it? The last time I looked at a physics text book (admittedly only at undergraduate level) fermions and bosons were very much still in the picture. Do you have a reference to research that is trying to do away with them?

Science is description. The idea is to make really good descriptions. As mathematics, it all works pretty well. As language, well, language comes with its own set of problems. For example, what, exactly, do you suppose the author meant by "common sense"? Working through that renders the essay moot. — tim wood

In the article I linked to it seems pretty clear that the author is talking about that part of commonsense that views the world as populated with colourful, shaped and solid things, and physics is supposed to undermine that (at least that seems to be the gist - the argument is attributed to Bertrand Russell).

As to taking physics etc as offering pragmatic models, isn't that just exactly to adopt the instrumentalist view that the article's author recommends?

I think the realist you are talking about has at a bare minimum just four metaphysical commitments:
1) that there are things that perceive
2) that there are things that are perceived
3) that there are perceptual relations between these things, i.e. relations we indicate with verbs like "to see", "to hear", "to touch" and so on.
4) neither of the types of things (1) or (2) depend for their existence on the fact that those relations sometime hold between them.

Empirical idealists, like Berkeley and perhaps Bohr - although I cannot be sure about him - deny (4) and claim instead that things that are perceived depend for their existence on being perceived. You can find his arguments for that conclusion in the first Dialogue Between Hylas and Philonous.

Where does this leave the moon when everyone's gone to sleep? Berkeley's answer was that God never sleeps, and perceives all things at all times.