Physicalism is an extreme form of materialism that says that only physical entities exist. This differs from more moderate forms of materialism like property dualism or emergentism where immaterial entities are acknowledged, only that immaterial entities like consciousness come from some type of material like the brain. Physicalism is a rigid monistic philosophy that places all existence into one category of being, viz., material beings.
One often hears from atheists all over the internet that only physical beings exist, that there’s nothing more to reality than matter and energy within space and time. They typically argue that anything immaterial is non-existent or strongly suspect to be unreal. They think that only physical beings can be known for certain to exist and that only physical beings have been evidenced to exist. Any belief that immaterial entities exist is baseless and a form of religious belief or a belief in the supernatural. All this sums up the common view among atheists. This position is clearly wrong.
Now I am not an atheist but even if I were a staunch atheist, I would never uphold this absurd position. Note it’s possible to be an atheist and to be one that endorses the existence of immaterial beings. The proposition of atheism by itself only says that there is no Divine, and not that there are no immaterial entities. So let’s forget about the atheist versus theist debate for the moment and just focus on the mere question of immaterial entities.
It’s typical thinking that “immaterial entities” are only attributed to spiritual beings that are postulated by religion. However, the category of immateriality is not restricted to the list of entities that are generally posited by religion such as God, angels, demons, and souls. Other types of entities can also be categorized as non-physical such as concepts, propositions, syllogisms, numbers, moral properties and consciousness. And some thinkers throughout history (like Isaac Newton) and even today would argue that space is something that should be considered immaterial.
It’s worth noting that an immaterial entity is not something that’s necessarily a “supernatural” or “extra-natural” entity. A supernatural entity would be an entity that exists independently and beyond the universe or nature like God or perhaps platonic forms. But an immaterial entity may be something that’s a part of nature or very much dependent on the conditions in the world like one’s consciousness. The souls of animals and human beings may be entities that are immaterial but not strictly supernatural since souls are a part of the natural world. A non-physical being might be “supernatural” but that’s not always the case.
How is something immaterial? By being an existent entity that does not share in the same set of common traits that are attributed to physical objects. Physical objects have size, shape, weight, divisibility, and are composed of stuff, whereas immaterial entities like our mental states lack those traits. Leibniz’s Law of Indiscernibility alone is sufficient to distinguish conscious states from material objects. After all, if material entities don’t share in the same features as mental states then by Leibniz’s principle they are not numerically the same thing. That’s how immaterial beings are distinguished from material beings.
It’s clear that immaterial entities exist from our everyday experience. Contrary to popular misconceptions, proving the existence of immaterial entities does not require showing anything extraordinary or unusual. No one needs to see a ghost or a miracle, for instance, to know that non-physical beings exist. It’s evident that non-physical entities exist from our everyday consciousness like an image of a white rabbit in a dream. A dream image of a white rabbit isn’t composed of atoms; it’s not a material or living thing in the world.
Nonetheless, the dream image of the white rabbit exists in that it’s being perceived by the dreamer. That’s already a proof that immaterial entities exist. Not only is there evidence that clearly shows that immaterial things exist but I would also add that the existence of immaterial entities is more certain than the existence of material entities. Sound far-fetched? Take a brief look at Descartes’ 1st and 2nd Meditations.
In the First Mediation, Descartes calls everything into doubt and supposes that maybe his life experience is due to an evil genius or demon that simply projects images of chairs, tables, persons etc. into his consciousness while none of those objects really exist or have the mind-independent existence that people normally attribute to things. In other words, the argument says that one could be in a “matrix” or in a mere world of ideas or sense-images that are projected by some demon. (We now commonly refer to these thought experiments of being in a deceptive world as a “matrix” thanks to that 90s science fiction film, The Matrix). There are several different illustrations of this type of argument like a person being a brain in a vat or a person plugged into a matrix by extraterrestrials or a person being hexed into a lifelong dream by a wizard or whatever the scenario may be. The idea that we’re in a computer simulation or the so-called “simulation hypothesis” may also be another “matrix” scenario.
Early within the Meditations, Descartes concludes that his own consciousness is completely certain. This is because there’s no way to override the fact that one is conscious. Whether one is in the “matrix” or not, one’s consciousness remains certain. Even if the dream and evil genius arguments successfully show that we are not completely certain of the existence of the external world, or even if we are living in a matrix, all this would be quite irrelevant in overriding our knowledge of our mental existence. In fact, to be deceived in a matrix or lifelong dream or to be deceived about anything at all would logically imply that one is conscious. Rocks and trees cannot be deceived about anything because they are not sentient beings. Only conscious beings with a certain degree of intelligence can be deceived.
The point of bringing up the matrix thought experiments is not get anyone to doubt the existence of the world. The existence of the external world is a rational, strongly evidenced belief even if it cannot be absolutely proved to exist. The point is that the matrix thought experiments like in Descartes show that it’s at least logically possible or a coherent idea that consciousness can exist independently of material objects without implying contradiction.
If it’s logically possible that one can be in matrix created by a demon where there are no material objects in existence then this seems to show that consciousness is not identical nor reducible to physical entities and that it’s possible at least in principle that one’s awareness and thought can exist even when there are no physical beings out there. Supposing that one is experiencing sense-impressions created by a deceptive angel with no actual material objects is not like supposing that a triangle can exist with having only one side. We have something similar to this with dreams where a person perceives what looks like a physical environment without there being any physical objects around. Of course, the evil genius thought experiment doesn’t prove that consciousness does in fact exist independently of matter. However, the thought experiment demonstrates that consciousness cannot be strictly identical to material beings.
The matrix thought experiments like in Descartes also seem to illustrate that one’s consciousness is more certain than the existence of physical entities. Again, there’s no logical contradiction in the notion that one’s belief in the existence of extra-mental physical entities can be overridden and corrected by future evidence like if one wakes up and discovers that one has been living in type of a matrix or a dream or perhaps one dies and goes into the afterlife and learns that one has been living in Berkeley’s idealist world—a world where physical objects are only ideas among minds.
An afterlife, of course, would imply that consciousness could exist without any material entities being around.
It may be logically possible that one could be mistaken about there being external material objects in existence. However, it’s logically impossible that a person can discover that she is in error in thinking that she’s conscious. Being liberated from a matrix wouldn’t override knowledge of one’s awareness and thought like it might for one’s belief in material objects. To think, believe, doubt, or to be in error is to always presuppose that one has consciousness. One’s mental states can never be overridden by evidence no matter what the future unfolds. All evidencing can only happen in the context of a conscious being. Hence, certain immaterial entities viz., mental states are more certain than the existence of physical entities.
Thus, physicalism is not a credible position whatsoever because the mental (or immaterial in that regard) is more certain than the physical and the mental is irreducible to the physical realm. We can even demonstrate that consciousness is irreducible to physical beings given the terms of physicalism.
Materialism in all its forms defines physical things like chairs, tables, brain cells, etc. as extra-mental entities. In other words, a materialist thinks that physical objects exist outside one’s mind or conscious states. So when three people look at one chair in a room they are only looking at a single chair in that room. The materialist has to define physical entities as extra-mental entities to safeguard his ideology. If physical objects are however defined as mental entities that are merely inside our conscious perceptions like a mental image in a dream or a hallucination then this view of material objects would collapse into the theory of idealism and it would imply that physical entities have their origin in mind or consciousness contrary to materialism.
Also if physical beings are mental entities as the idealist would say, then three people looking at the appearance of one chair in a room would really be an instance of three people looking at three different chairs. Why? Because if physical entities are mental entities then there would be as many physical entities as there are minds that perceive them as such. So the materialist has to define physical objects as extra-mental entities if they want to consistently argue that consciousness has its origin in some outside, external source, viz., matter and energy. Otherwise if idealism is true and physical objects are only mental entities then consciousness cannot emanate from matter; rather it would be matter emanating from consciousness.
Now if physical objects are defined as extra-mental entities then there is no hope of ever showing that conscious states are identical to neural activity or anything physical. Not even the most advanced neurobiology can explain how subjective awareness can be identical to something that is, by definition, outside and distinct from the realm of the mental.
If physical objects exist independently of our perceptions of them then mental states cannot identical with physical entities. (After all, if a chair or a brain in a surgery room isn’t being multiplied every time there’s an extra observer in the room then that implies that the material entities are not identical to mental activity). This is also reinforced by the fact that the materialist generally wants to say that matter causes consciousness to exist but consciousness itself doesn’t cause matter to exist. And that causal distinction already implies a real difference between mind and matter altogether. Therefore, mental states can never be identical to matter and energy and its properties particularly if physical entities are defined as objective, mind-independent, extra-mental entities.
The physicalist may then realize that mental states cannot be reduced to material beings like the brain. The physicalist might try to get rid of consciousness altogether to preserve the notion that only physical beings exist. If the physicalist makes this move then he would be favoring “Eliminative materialism” or the notion that we are mere bodies or “zombies” with no real consciousness. Now eliminative materialism is clearly wrong and saddled with hopeless absurdities but it seems to be the logical implication of physicalism. After all, if only extra-mental physical beings exist then how would there be any room for mental phenomena?
Now it shouldn’t require a refutation to know that eliminative materialism is bunkum. Clearly we have conscious states. Nonetheless, I’ll describe a few incoherencies within this extreme form of materialism to further my case against physicalism. Eliminative materialism fails to explain our knowledge of material objects. The eliminativist wants to say that physical entities are the only things that exist. But how can the eliminativist know or so much be rationally justified in believing that material entities exist if consciousness doesn’t exist? Doesn’t a person have to be observant of things in order to realize that physical objects exist? How can the eliminative materialist account for the existence of external objects without presupposing consciousness, (e.g., seeing, hearing and touching)?
To argue that one can be justified in believing that material objects exist without conscious perception is like trying to make a sound argument without implying the Law of Identity (the logical principle that says “whatever is, is”). It’s not something that can be done! The eliminative physicalist cannot even “know” that physicalism is true or even that physical objects exist by his own terms because to know or evidence anything would imply consciousness. Unless an insentient being like a rock can know things or realize its own unconsciousness, the eliminative materialist has no hope of knowing their own position to be true given their ideology.
As many have also pointed out, eliminative materialism also implies a contradiction about beliefs. If we take eliminative physicalism seriously it would entail that people do not have beliefs. This is because beliefs are mental entities and all mental entities are non-existent or “folk psychology” for the eliminative materialist. But then the physicalist would be trying to persuade us to believe that we have no beliefs. He would be implying that we ought to have a belief about beliefs. The eliminativist would be telling us that we ought to think that we have no beliefs. However, a denial of the existence of beliefs would have a real belief behind it. Daniel Dennet, a philosopher that promotes eliminative materialism tries to persuade people that it’s true and yet he cannot even be said to “believe” it’s true given his own worldview!
Does eliminative materialism offer a solution to Leibniz’s problem with materialism by denying that the brain produces consciousness and that the brain only produces an “illusion of consciousness”?
Obviously not. An unconscious brain cannot produce an illusion about anything. Again, it would be a contradiction in terms to say that a completely unconscious brain can produce an illusion or misimpression about anything. Also consciousness cannot be discarded as “illusionary;” for to have an illusion about anything would presuppose consciousness.
Whether the perception is misleading or not, it is still perceiving something or being conscious of something. Besides, an endorsement of eliminative materialism would be an implicit agreement with the fact that physicalism cannot accommodate subjective experience. But if that’s the case, then physicalism should be rejected off hand and it shouldn’t go the other way around where one denies consciousness in order to religiously uphold physicalism. It’s unbelievable why anyone would bother to defend eliminative materialism when one can refute it by simply referring to their own mental experience. But then again, eliminative materialists have to admit that they don’t believe in physicalism as well, since according to their own ideology, there are no beliefs!
The physicalist cannot coherently reduce consciousness to physical beings, nor can the physicalist coherently exclude consciousness in order to save their monist paradigm. Physicalism is incompatible with consciousness. The mind simply cannot fit within the absurd monistic position that only external, non-mental, material entities exist. Other monist philosophies like neutral monism and idealism may be logically compatible with our conscious experience but physicalism however is not compatible with subjective experience.
Moreover, physicalism entails that there is no such thing as truth and it greatly undermines the discipline of logic. The existence of truth requires the existence of truth bearers or entities that have the features of truth and falsity. The only possible candidates for truth bearers are immaterial meanings or contents that are understood by the mind. Whenever one understands that “2+2=4” is true and that “2+2=7” is false he isn’t saying that some physical object is true or false, he is rather holding that the understood content that’s expressed by the language is true or false.
And it doesn’t matter whether our truth bearers are mental entities like judgments or extra-mental timeless contents like ideal entities. Either way, the truth bearers have be immaterial and not material. Likewise with logic, we imply that meaning or content is something non-physical all the time. In judging arguments or syllogisms to be valid or invalid, we are not judging any material object like a chair or table to be valid or invalid; we are rather judging the understood content to be logically valid or invalid. Because physicalism cannot accommodate the existence of abstract entities in any form, it entails that there is no truth and that there’s nothing out there that can be considered logically valid or invalid. So if physicalism is true then paradoxically it isn’t true.
Thirdly, even if physicalism were “true” there would be no way of discerning its truth. Supposing if physicalism could adequately account for consciousness, truth, logic and other features of the world, there would be no way of knowing it to be the case. Even if physical beings were the only known entities to exist, it would not imply that only physical beings can exist. The mere existence of material beings doesn’t prevent there being immaterial entities out there. It’s like knowing that there’s life on our planet and that this knowledge doesn’t preclude the possibility of life on other planets.
Also, the exact mode of the “existence” of physical entities is something quite debatable and not everyone agrees with the physicalist that material objects have an absolute, mind-independent existence. Some argue for idealism and say that material beings are only ideas or perceived objects within our minds and that material things have no extra-mental existence. Others might grant that physical entities have an extra-mental existence but are nonetheless dependent on the Mind of God for their existence. With many forms of theism, material entities wouldn’t have the absolute mind-independent existence that materialists attribute to them. If there’s a Deity by which all entities are caused to exist, then physical entities would be dependent on a transcendent Mind for their existence. There’s nothing in our experience that shows that material objects should exist absolutely independently of all minds.
In conclusion, physicalism is not a rational position. It fails to account for the reality of consciousness and other features of our everyday experience like truth and logic. Physicalism carries with it a bold and universal statement about existence that cannot be proved, known, verified, or even presumed to be true. In other words, physicalism is only a quasi-religious dogma that has no evidence backing it and plenty of evidence that refutes it.