Apologies for my English.

Some thoughts from the camp of idealists. :)

The following is the explanation of the question in the title.

I think that the fact that in our days physicists may be materialists or idealists does mean something. It means that physics itself can't claim by proof or evidence which ideology is true or false.

Ideally, all empiric sciences should be no more than a synergy between empirical evidence and maths. They really shouldn't be taken as tools that by themselves are capable of providing ontological proofs.

One brilliant materialist, Bertrand Russel, wrote:

Of course it is not by argument that we originally come by our belief in an independent external world. We find this belief ready in ourselves as soon as we begin to reflect: it is what may be called an instinctive belief. We should never have been led to question this belief but for the fact that, at any rate in the case of sight, it seems as if the sense-datum itself were instinctively believed to be the independent object, whereas argument shows that the object cannot be identical with the sense-datum. This discovery, however—which is not at all paradoxical in the case of taste and smell and sound, and only slightly so in the case of touch—leaves undiminished our instinctive belief that there are objects corresponding to our sense-data. Since this belief does not lead to any difficulties, but on the contrary tends to simplify and systematize our account of our experiences, there seems no good reason for rejecting it. We may therefore admit—though with a slight doubt derived from dreams—that the external world does really exist, and is not wholly dependent for its existence upon our continuing to perceive it.

After some thought and study it should be obvious that something independent of our perceptions has to exist. Our perceptions obey the very complex and somewhat stable Model (I'll uppercase the first letter of this world to distinguish the meaning when it's not obvious). The only narrow part of this model is studied by physics.

Materialistic (or physicalistic in modern terms) approach seems to suggest that the model and its submodels that rule all our experience are derivatives of objects that exist in time and space, and there is nothing except these objects in time and space. And these objects, including time and space, by themselves obey some rules that bit by bit are learned by physical science.

This approach is a model by itself. It's obvious that it is inspired by habitual mental templates which are partly inspired by the Model itself, since our perception loops behave like there is an independent external world which is similar at least in time and space to how we perceive it.

Well, try to use the materialistic model on virtual 3d worlds like those in PC games, and it will become obvious that this approach will not only bring an unnecessary complexity, but will bring us to a completely misunderstanding of the infrastructure for such virtual world and to a totally false ontology!

It seems that at some point in future it will become technologically possible to translate virtual worlds directly into perceptions via interfaces known as brains. After that it will be much harder till impossible to distinguish between the 'real' world and the 'virtual' one.

The much more simple way is to recognize: all that is required for our existence is a 'screen' as a 'place' for our perceptions (from colours to thoughts), a model for regularity, and something to produce the both.

The materialistic approach requires the 'screen' (brain) and a model (physical rules) too, but it also requires a zillion of unnecessary things + something unknown that would be a reason for all these to exist (like a reason for the Big Bang).

Occam's razor rests in peace.

As for qualia like colours, sounds, pleasure, pain, etc.. - I personally didn't found how the suggestion that they are nothing more than physical objects can be consistent.

Let's talk about colours. If they are nothing more than waves with certain frequencies then we should see colours before these waves reach our eyes. Because after that these waves stop to exist as waves. If colours are nothing more than affected by those waves groups of neurons then these neurons must be coloured with the perceived colours for something that is capable to perceive these neurons as colours in exactly the same form as they're seen by a person. In this case this "something" would be or the same coloured neurons, or some other neurons, or something else. If it is the same coloured neurons, then we're going to conclude that colours are perceived by colours... If it is some other neurons, than colours as they're seen are in those other neurons, thus the coloured neurons aren't really colours... If this is something else, then we should look for some other physical entities, but for any candidate the coloured neurons won't be the colours themselves. In general, the problem in the materialistic approach, that it requires some physical entity to be a colour as it is seen, and some (maybe the same) physical entity to actually perceive this colour. If a colour and a percipient are the same entity, then a colour is seen by a colour. If they are different entities, then the perceived entity exists in the perceiving entity as the colours exist in us when we're seeing them. Thus, if we aren't radically different from our brains, then some parts of our brains should be coloured literally - otherwise they aren't colours. In short, the requirement for some non-colour to provide colour leads to nonsenses.

Obviously, there is a mapping between different colours and measurable properties of light waves. But it seems to be nothing more than a mapping, provided by the Model. And maybe, this mapping is different for different persons - if such different mappings provide the same regularities within the Model then we can never know that some person sees green while other in the same place and time sees red or blue.

Now, substitute the term "colour" with "sound" - what physical entity would be a sound in our brain as we hear it? The same seems to be correct about other qualia including pain and pleasure.

P.S. What we actually perceive is a somewhat ordered set consisting of its subsets that constitute different kinds of data like colours, sounds, feelings, thoughts, etc.. This set is regularly changing, and whenever we point at different subsets in different times and state that they represent the same thing - we abstract from differences and populate our mind with objects of the so called "external world". Thus materialism seems to be a belief that these abstractions must exist by themselves. For whatever reason.

  • 2
    I think this is a great question, but I suggest some editing work to make it more likely that people will read through it. Also, do you have any more citations? I am guessing that the colour argument has been made elsewhere?
    – labreuer
    Nov 14, 2014 at 18:19
  • Thanks for your comment! I'd like to make the text more readable. Unfortunately, I'm unlikely capable of improving my English this fast. If English isn't the case, what in your opinion I can do to improve the readability? The 'colour argument' is taken from my thoughts about the subject. Bertrand Russel wrote about colours (among other things) in his 'The problems of philosophy' work. I'm sure that I encountered different 'colour reasonings' in other works, and if I borrowed this specific one, it was kind of unconsciously.
    – a1111exe
    Nov 14, 2014 at 20:25
  • 2
    The discussion about colors reads like something out of the 18th century. Have you read about the neuroscience of color vision?
    – Rex Kerr
    Nov 16, 2014 at 20:05

3 Answers 3


There's no inconsistency between the reality of qualia and materialism unless one has an excessively reductive conception of "the physical" -- using things like Locke's inverted spectrum and "Is your red the same as my red?" to try and prove the mind has its own special reality (i.e, with its own special laws unrelated to the physical) is this kind of reduction. It starts with the presumption that the experience of color is obviously/intuitively/common sensically non-physical and therefore neither is the mind.

We can instead presume that the experience of color is physical, but not so simplistic as to exclude the possibility of random inversion or eccentric differences, etc. There aren't any thought experiments involving qualia that problematize the idea that they are physical, they simply reveal that the physical world may be a more complex place than was assumed.

The point of materialism/physicalism is NOT to understand the mind completely in terms of physics, although it follows that in theory a more advanced science than ours might be able to do so.

The point is that the mind does not possess any special qualities other than physical ones. Starting from this perspective, theories which implicitly or explicitly require such special qualities can be deconstructed on the basis of the special requirement, like pulling apart a sweater starting with a loose yarn.

This doesn't really have much consequence for contemporary psychology, psychiatry, neurology, etc. These would all be the same and continue to proceed the same way whether or not the physicalist premise is true, much the same as physics is the same regardless of whether or not there's a God. As I'm sure we are all aware, many physicists are dualists and there is no inconsistency there.

Materialistic (or physicalistic in modern terms) approach seems to suggest that the model and its submodels that rule all our experience are derivatives of objects that exist in time and space


  1. Not all physical phenomenon are "objects".

  2. The belief that our conscious experiences are derivative of physical phenomenon is a dualist/metaphysical one, not a materialist one. The materialist position is that our conscious experiences (qualia) are physical phenomenon.

This last point might be considered a minor semantic one, if your dualist conception ends at the mind (which is why, again, the distinction doesn't change anything about secular psychology and so on). However, it is a little hard to see the point of such a conception, and arguably this would likely be a remnant of some more elaborate (theistic) metaphysical system.

I think there is a lot of confusion about what "physical phenomenon" refers to. It refers to things which can, or could (assuming perfect knowledge) be explained in terms of physics.

The "perfect knowledge assumption" is important; it could turn out that human beings are simply not capable of achieving such a thing. The point of the assertion is that if they did, the mind would be understood to be completely physical. This is in contrast to the claim that, assuming perfect knowledge, we would know the mind is decisively something other than a physical phenomenon.

The materialistic approach [...] also requires a zillion of unnecessary things + something unknown that would be a reason for all these to exist (like a reason for the Big Bang).

The materialist approach is that nothing other than the physical world is required to explain anything, period. It not only does not require a reason for the physical world to exist, it pretty much insists there can be no such thing as a reason for it to exist.1 If you find this problematic, then you have metaphysical aspirations (conscious or unconscious).

Obviously, there is a mapping between different colours and measurable properties of light waves. But it seems to be nothing more than a mapping

Yes, but this is not an objection to physicalism. This is (I referred to this in a parallel discussion), the difference between the map and the territory, not the difference between a physical phenomenon and a non-physical experience. If I show you a map of a city and you use it to find a building downtown, the map and the territory are, indeed, very very different, and our power to reason allows us to make the connection between them.

1. To clarify, this is not to say there was no reason for the big bang. Almost certainly there was, but it was a physical reason. WRT Occam's razor, that is the simplest option. "Multiplying entities" does not mean increasing the number of something that already exists; a house with five rooms is as likely as a house with two rooms by Occam's razor. It means not adding new kinds of entities that otherwise don't need to exist (e.g., a house with five rooms full of ghosts). From this perspective, multiverse theories are not objectionable because they don't claim there is some new realm that cannot be analyzed in physical terms. They claim there is more than one room in the house.

  • Thanks for your answer! I see that I can argue, but comment limits leave no room for rhetoric...
    – a1111exe
    Nov 14, 2014 at 21:12
  • @a1111exe You may be one of the people who chooses to invite people to chat, instead... Chat is not necessarily synchronous, but allows for longer discourse.
    – user9166
    Nov 16, 2014 at 18:19
  • That's a good idea. You need 100 rep to create a room but only 20 to use one, so: chat.stackexchange.com/rooms/18705/… Should work. I can't find the "invite" button but you should be able to click through (when you see where I wrote "Okay! Fire away.", you're there). Those rooms are more or less permanent; you can use @ and a username to notify someone whose used it (e.g. @goldilocks). There's a limit to the individual message length but you can leave as many consecutive messages as you think someone is likely to read ;) Nov 16, 2014 at 18:36

If thoughts are not so much built up, but sifted out of an over-determined, self contradictory mass, we don't need to find the cause, we need to find the validation mechanism that decides which thoughts 'win' and become conscious. We have strong examples from perception that make us trust there would be such a mechanism, even if we cannot place it well in the brain. Daniel Dennett (in Consciousness, Explained) captures some aspects of how such a process might work, by giving a paper model of it.

The same way, the brain does not have to contain colors, or even models of colors, just models of models of colors, in order for us to imagine a purple cow. The 'purple' does not have to be there, it just has to be the best model of what we want, for the model of models to judge the quality of it highest.

And we are pretty sure that our experience does contain models of models, not only of real things, but of fake ones. We make models of models of things inside computers all the time. Take the game simulation of the physics of a pinball machine, for instance: There are no balls there. There is no physics there (which is a real model of how the balls would really act if they were real). But there is a simulation of the physics using simplified arithmetic and limited-precision numbers. So while a real thing, or a 'real model' of a thing may not be the something we can imagine being physical, we see something that would provide this function, in our own creations.

Like a lot of direct idealism, all of this seems either highly presumptuous or outright circular. We know that things don't have to be as they appear, so reasoning from appearances is not wise, until you consider all the ways they may be side-effects of the process, instead.

To me, an idealism that rejects physicalism has to account for all the flaws in your perception (without falling back on a physical model) the same way that a physicalism that rejects idealism has to develop convincing mechanisms for its success. Otherwise Occam's razor says we should choose the model they both need and reject the one that only the idealists need. Physicalists seem willing to do their part of the work here, most idealists do not seem willing to really address theirs.

To my mind the closest anyone comes to explaining why in an idealist's world we would still not comprehend things properly by default is in studying neurosis. And idealist philosophy does not really take any form of psychodynamics seriously or see it as part of their enterprise.

I am more interested in a more physically and sociologically modern version of Kant, which would harmonize both, but only after each side takes the other seriously.

  • In some similar discussion my opponent told in the end that in his opinion all mental things including the colours aren't real, and just don't exist, that's it. Well, maybe for some physicalist the colour I see is a kind of illusion in the end of real physical process. But for me (and, I suppose, for anybody else) this colour is an example of a concrete existence in my (his/her) perception, while all physical processes are merely a posteriori abstractions. Thus, if some physicalistic attempt just discards my own empirically proven (at least for myself) reality, than I'll surely doubt it.
    – a1111exe
    Nov 16, 2014 at 19:15
  • The burden of proof is on the person doing the proving. I don't really care what you believe, if you don't care to take arguments against it seriously. The point of philosophy, for me, is to find the full range of what we can communally believe, and that requires taking all the evidence into account. I buy Hegel's notion that qualia and physics are mutually caused and that the primary act of reasoning is to unify them. So I am a non-player here. I argue equally against oversimplification on both sides.
    – user9166
    Nov 16, 2014 at 19:24
  • The comment I put here got too long, so I appended it to the post.
    – user9166
    Nov 16, 2014 at 19:49
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    Leibnitz and later Whitehead really tried, but they succeed mostly at being incomprehensible and therefore impossible to argue with directly. They manage, at best, to embed physical reality in an ideal world, by presuming distortion is just an aspect of the imitation, while complaining that all physicalists manage to do is embed idealism in the physical by assuming qualia are epiphenomena.
    – user9166
    Nov 16, 2014 at 20:09
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    If the issue is really monism vs dualism, then Occam's razor removes idealism, not physicalism, because a certain part of our perception can be seen to be caused only by interference of physical phenomena in the process. Why assume the rest is not just part of physics?
    – user9166
    Nov 16, 2014 at 20:28

Some of the questions asked in the philosophy stack exchange are such that they can be met with a good answer in a few paragraphs. The question whether the argument from qualia defeats materialism is not one of these questions. It is a question that the smartest philosophers in the world continue to debate. Your best bet is to take a look at this literature. In particular, you might enjoy Frank Jackson's papers. His argument against materialism, called the knowledge argument, was for a while considered by professional philosophers the best argument against materialism. Unfortunately for the dualists, Jackson reversed his position about a decade ago. This reversal is known as Jackson's apostasy. His new position is called representationalism, and has been very influential. You might also find functionalism interesting, as it is closer to a dualist position on mind body than representationalism. There do remain some highly respected hard-core dualists. In any case, your best bet is to start exploring the literature.

Here are some links you might find helpful.

Edit: I also gather from your question that you might be interested in the question why it is rational to believe in physical reality before mental reality. The best exposition here is to be found in the first chapter of Quine's Word and Object.

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