Arguments for Physicalism (A comprehensive guide)


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Page last updated: 30/09/2022

Arguments for Physicalism (A comprehensive guide)

In this guide, we will discuss some of the Arguments for Physicalism and also some of those against it.  Even if there are divided opinions, we will mention some key aspects to consider when accepting or rejecting physicalism. 

Arguments for Physicalism

The arguments for physicalism, we would understand them as in favour and against it, include the causal argument which can be summarised as:

  • Mental properties have physical effects.
  • Physics is causally complete, where physical effects have physical causes.
  • Effects are not generally overdetermined.
  • Mental properties are physical.

From the premises or arguments we have talked about, they seem to rely on common-sense, empirical support and they are a priori statements. Physicalists maintain that all of the mental states and processes in the human mind are physical. Physicalism rejects dualism in the sense that dualists argue that mental states are non-physical states.

The first thing we could say to consider the truth of physicalism is that we live in a physical and materialist intellectual culture. This results in lowering the standards of arguments required to persuade someone of the truth about physicalism than those who reject it. However, it might be difficult to assess the arguments for or against physicalism such as the one called ‘the argument from causal closure’ or ‘the argument from methodological naturalism’.

Arguments for mind-brain identity

The thesis of the mind-brain identity argues that the descriptions of our mental states and the ones that describe our brain states are in fact descriptions of the very same thing. This identity-thesis holds that all the mental states and events can be reduced to physical states and events. However, it doesn’t mean that concepts such as pain or self-image may be analyzed or defined in terms of brain processes. 

The central thesis about the things that exist in the world to which our words refer to, hold that we have different ways of thinking represented by our terms for conscious states and also by some of our terms for brain-states. 

Physicalism and consciousness

One of the most powerful arguments for this view, and many physicalists would agree, is known as the causal argument and it is the thought that unless the mind were physical, it couldn’t have effects in the physical world. Descartes was one of the most famous anti-physicalists that argued that there were two separate realms, the mental and the physical. But other philosophers criticized his point of view arguing how if they are so different, they can affect each other. 

Going back to our main argument, we would have to assume that mental events have physical properties or effects. In general, we believe that feelings, thoughts and decisions are mental events that have effects on the body and thereby, have the power to influence the physical world.

For our second premise, physical effects can be fully accounted by a prior history of physical causes. For instance, we could talk about how neurons release neurochemicals to communicate with each other allowing me to transform this into thoughts. But some might argue that premise one and premise two would have been enough acting on its own. 

However, we would need to consider our third premise as the physical effects of mental causes aren’t all overdetermined and here we could be tempted to argue that mental causes are themselves out of the physical world.

Arguments for Physicalism (A comprehensive guide)

The knowledge Argument Against Physicalism

If we mention arguments in favour of physicalism, we need to also include some of those against it. As this argument claims, there are truths about consciousness that can’t be reduced from the complete physical truth. For instance, Frank Jackson’s Mary is believed to have learned all the physical truths from within a black-and-white room but when she leaves the room, she sees red for the first time and learns new truths. 

Contrary to what physicalists might say, the complete physical truth is not the entire or whole truth. This physical truth does not determine metaphysically, the whole truth about the world. As indicated by Tony Alter from the University of Alabama, there are eight controversial assumptions and we will mention just some of them:

  • The notion of the physical is coherent.
  • The complete physical truth is accessible to the pre-release of Mary.
  • Upon leaving the room, she learns something.
  • The kind of knowledge she acquires upon leaving the room is informal knowledge, rather than ability knowledge, acquaintance knowledge, or something else. 
  • She gains new information, rather than old information represented in a new way. 

The knowledge argument aims to reject physicalism, which argues that the world is entirely physical but many reject this idea since they argue the subjective aspect of the mind is physical. If we go back to Mary’s example and we were to argue that physicalism is true then Mary should know everything there is to know about human colour vision before leaving the room. 

However, since Mary learns something new when she leaves than she learns about qualia, which are the properties that characterize what it is like to see colours, therefore physicalism is false.

Meaning and Intentionality

Philosophers of the mind have been facing two problems in regards to physicalism:

  • There are problems of qualia, typified by the knowledge argument.
  • There are problems of the intentionality of mental states and their capacity of representing the world as being a certain way. 

As indicated in, “One does not simply think, one thinks of (or about) Vienna; similarly, one does not simply believe, one believes that snow is white. Just as in the case of qualia, some of the puzzles of intentionality derive from facts internal to the notion, and from the relation of this notion to the others such as rationality, inference and language.”

However, others consider that it seems difficult to picture mental states having intentionality in physicalism. For additional information about this argument, we recommend reading Kripke’s approach. 

Methodological issues

This can be considered the final argument against physicalism from a methodological perspective. Physicalism is not suggested to be false or whether it is true but it seems to be misguided. Noam Chomsky is believed to be one of the most known advocates. 

Chomsky’s criticism begins with two points about methodological naturalism. Generally speaking, it seems rational to agree with methodological naturalism that indicates how the best hope for a better understanding of the world goes hand in hand with the purse of the methods that are typical to the sciences. 

Secondly, Chomsky argues that the physicalist project in the philosophy of the mind is on the face of it rather than being differentiated from the naturalistic project. Initially, the physicalist project is thought of a piece of metaphysics. However, there is nothing metaphysical about the naturalistic project which may raise the question about what we can hope to explain.

Additionally, the physicalist project is normally considered to be amenable to the philosophical argument, whereas it is completely unclear where philosophical arguments would enter the naturalistic project. In other words, there doesn’t seem to be anything philosophical about the naturalistic project. 

Why is this blog about Arguments for Physicalism important?

The arguments for physicalism are important for those who try to establish if physicalism is true or if it is meant to be rejected. However, alongside the literature, we might find divided opinions and many arguments to consider. 

Moreover, the arguments for physicalism would be considered as in favour or against, when we include the causal argument which can be summarised as Mental properties having physical effects, Physical is causally complete, where physical effects have physical causes and the effects are not generally overdetermined. Finally, mental properties are considered as physical. If we analyze those key aspects we could have enough arguments in favour or against physicalism. 

Please feel free to leave any comments or thoughts about the content of this article!

Frequently Asked Questions (FAQs) about Arguments for Physicalism

What is Physicalism philosophy?

Physicalism in philosophy is the thesis that argues that everything is physical or as some contemporary philosophers indicate: everything supervenes on the physical. This can be compared to the idea of ancient Greek philosophers where everything was water or Berkeley’s idealism where everything is mental. However, in this case, the general idea is that the nature of the actual world is physical. 

What is the knowledge argument against Physicalism?

The knowledge argument is one of the main challenges to physicalism, where the main argument or thesis is that the world is entirely physical. This argument begins suggesting that there are truths about consciousness that can’t be deduced from the complete physical truth. 

What is the difference between materialism and Physicalism?

The difference between materialism and physicalism, even when they are words that are often used interchangeably, materialism argues that matter exists and the various motions that happen between objects of matter. However, physicalism is the doctrine that only the physical exists.  

What is non-reductive Physicalism?

Non-reductive physicalism is understood as the view where mental properties form a separate ontological class to physical properties. Those mental states are not reducible to mental states. If we consider it at a first glance, we could say that it seems to be a form of property dualism in the sense that everything has both mental and physical properties.

What is the hard problem of consciousness and why is it so hard?

As mentioned on, “The hard problem of consciousness is the problem of explaining why any physical state is conscious rather than nonconscious. It is the problem of explaining why there is “something it is like” for a subject in conscious experience, why conscious mental states “light up” and directly appear to the subject.”


 Yates, David (2008) The Causal Argument for Physicalism. Doctoral thesis, UNSPECIFIED.Retrieved from

Alter, T. (n.d) The Knowledge Argument Against Physicalism. Retrieved from “Physicalism” “The case for Physicalism”