My question has two components:

  • Reasonableness. What does it mean for a position to be reasonable? What conditions does a position have to meet to be regarded as reasonable?

  • Physicalism. Wikipedia defines it as follows:

    In philosophy, physicalism is the metaphysical thesis that "everything is physical", that there is "nothing over and above" the physical, or that everything supervenes on the physical. Physicalism is a form of ontological monism—a "one substance" view of the nature of reality as opposed to a "two-substance" (mind–body dualism) or "many-substance" (pluralism) view. Both the definition of "physical" and the meaning of physicalism have been debated.

    Physicalism is closely related to materialism, and has evolved from materialism with advancements in the physical sciences in explaining observed phenomena. The terms "physicalism" and "materialism" are often used interchangeably, but can be distinguished based on their philosophical implications. Physicalism encompasses matter, but also energy, physical laws, space, time, structure, physical processes, information, state, and forces, among other things, as described by physics and other sciences, as part of the physical in a monistic sense. From a physicalist perspective, even abstract concepts such as mathematics, morality, consciousness, intentionality, and meaning are considered physical entities, although they may consist of a large ontological object and a causally complex structure.

    Thus, non-physicalism can be understood as the thesis that physicalism is false, that is, the thesis that not everything is physical, or that there exists at least one thing that is not physical.

Is the belief in non-physicalism reasonable? How can someone reasonably conclude that physicalism is (probably) false? Is there any piece of data that might lend credence to the rejection of physicalism?

EDIT. Other suggested definitions of Physicalism:

Physicalism is, in slogan form, the thesis that everything is physical. The thesis is usually intended as a metaphysical thesis, parallel to the thesis attributed to the ancient Greek philosopher Thales, that everything is water, or the idealism of the 18th Century philosopher Berkeley, that everything is mental. The general idea is that the nature of the actual world (i.e. the universe and everything in it) conforms to a certain condition, the condition of being physical. Of course, physicalists don’t deny that the world might contain many items that at first glance don’t seem physical — items of a biological, or psychological, or moral, or social, or mathematical nature. But they insist nevertheless that at the end of the day such items are physical, or at least bear an important relation to the physical.


Physicalism is sometimes known as ‘materialism’. Indeed, on one strand to contemporary usage, the terms ‘physicalism’ and ‘materialism’ are interchangeable. But the two terms have very different histories. The word ‘materialism’ appears in English towards the end of the 17th century, but the word ‘physicalism’ was introduced into philosophy only in the 1930s by Otto Neurath (1931) and Rudolf Carnap (1959/1932), both of whom were key members of the Vienna Circle, a group of philosophers, scientists and mathematicians active in Vienna prior to World War II. While it is not clear that Neurath and Carnap understood physicalism in the same way, one thesis often attributed to them (e.g. in Hempel 1949) is the linguistic thesis that every statement is synonymous with (i.e. is equivalent in meaning with) some physical statement. But materialism as traditionally construed is not a linguistic thesis at all; rather it is a metaphysical thesis in the sense that it tells us about the nature of the world. At least for the positivists, therefore, there was a clear reason for distinguishing physicalism (a linguistic thesis) from materialism (a metaphysical thesis). Moreover, this reason was compounded by the fact that, according to official positivist doctrine, metaphysics is nonsense. Since the 1930s, however, the positivist philosophy that under-girded this distinction has for the most part been rejected—for example, physicalism is not a linguistic thesis for contemporary philosophers—and this is one reason why the words ‘materialism’ and ‘physicalism’ are now often interpreted as interchangeable.

Source: Physicalism | Stanford Encyclopedia of Philosophy

‘Physicalism’ looks at the view that everything that exists today—including human minds—came about in virtue of the rearrangements of and interactions between the physical particles and forces that emerged after the universe’s birth. There are a number of different versions of physicalism: identity theory, functionalism, mysterianism, eliminativism, non-reductive physicalism, and emergentism. The concept of multiple realization allows for the same type of mental states to have different neural signatures and contrasts physicalism with panpsychism, the view that the fundamental components of the universe are conscious. Most physicalists maintain the strongest philosophical argument for physicalism, what has come to be known as ‘the causal argument for physicalism’.

Source: Physicalism | Philosophy of Mind: A Very Short Introduction | Oxford Academic

  • 4
    There is no consensus on what "reasonable" means beyond vague colloquialisms, see e.g. Sols, Reasonable certainty. It is something like sound judgment for premises and informal validity for inferences, where "sound" and "valid" are taken pragmatically. Note that X and its negation can both be reasonable on this pragmatic standard at times. Non-physicalism argued from scientific findings, say (presumably sound), using induction, inferences to 'best' explanation, etc. (presumably valid) is reasonable.
    – Conifold
    Commented Mar 6 at 9:58
  • Something that cannot be explained, such as consciousness or general existence (either existential or physical) is therefore founded on something (as yet) undetermined. Indeterminate things appear as nothing, yet their products exist. One cannot say something indeterminate is physical; neither can one say it exists. That's as close to non-physicalism as I can suggest. Commented Mar 6 at 10:35
  • It's absolutely reasonable, if reasonable is taken to mean roughly, based on rational reflection and argument. But by definition, non-physicalist beliefs are generally non-empirical. The Navajo creation myth is quite reasonable for a Navajo member brought up in the legend. The same could be said of the Tlingit, or the Yanomami. But reasonable, rational narrative may conflict with physicalist beliefs. If the stories of various creation myths are compared with physicalist doctrine, then they tend to be articles of faith, because without empirical evidence, they are just stories.
    – J D
    Commented Mar 6 at 15:47
  • @JD But by definition, non-physicalist beliefs are generally non-empirical - Are you suggesting that the non-physical aspects of reality (if they exist) cannot be experienced? Can you please share a link to the definition of physicalism you are referring to, that rules out the possibility of experiencing the non-physical?
    – Mark
    Commented Mar 6 at 16:11
  • @JD Probably relevant: What are examples of non-physicalist approaches to acquiring knowledge?
    – Mark
    Commented Mar 6 at 16:12

12 Answers 12


First Question, is belief in a non-physicalist worldview reasonable

The key issue to consider to answer your first question is to realize how science is done. In a field of empirical inquiry the ANSWER is not yet known. It is often the case that as one does the science investigation, a particular framework could be more productive than another. But often we do not KNOW which framework will ultimately be the most productive, and in ill defined fields, there are generally multiple active frameworks. These frameworks are called Research Programmes. See https://antimatter.ie/2011/02/11/kuhn-vs-popper-the-philosophy-of-lakatos/

The scientific methodology is not the only one way to do philosophy, but as the most amenable to physicalism, it is a useful starting framework to apply to philosophic ontology, to see if even a pure science approach can justify the unreasonableness of non-physicalism. If the most pro-physicalist methodology for doing philosophy cannot support a pure physicalist POV, then it is reasonable to think that alternative ways to doing philosophy cannot support pure physicalism either.

So extending the scientific approach into metaphysics leads to: Physicalism is one Research Programme framework one can adopt. But philosophic ontology is about the LEAST mature area of study we have, so it would be surprising if it only supported one Research Programme. And that is the case. About half of philosophers in the Anglo-American space are physicalists. But the others are scattered among various versions of Idealism, Dualism, and neutral monism. So -- there are active non-physicalist Research Programmes that many intellectually serious people are productively pursuing.

This fact -- that there are serious active non-physicalist research programmes being pursued by philosophers -- alone answers your first question. Absolutely yes, it is reasonable to pursue a different Research Programme than Physicalism.

Second Question -- How can someone reasonably conclude that physicalism is (probably) false?

Applying the scientific approach to philosophy some more, physicalism then becomes a hypothesis about what the ultimate nature of reality is. For physicalism to BE such a hypothesis, then it has to be falsifiable. Anyone asserting it is NOT falsifiable, would then be making a pseudoscience claim. This is Popper's boundary criteria between science and pseudoscience. Your request for HOW that could be done, is something that any advocate of physicalism HAS to take seriously, and answer with specifics.

However, it is the nature of us humans that we are less able to see around our own presuppositions than critics of our presuppositions are able to, so it is perhaps the critics of physicalism that will be needed to help point such tests out. As a critic of physicalism, I will try to help my physicalist compatriots here.

The most insightful reference I have found on the REASON to hold by physicalism is The Rise of Physicalism, by David Papineau, here: https://www.davidpapineau.co.uk/uploads/1/8/5/5/18551740/papineau_in_gillett_and_loewer.pdf Note Papineau does not use Lakatos' language, but the explanation he gives for the rise of physicalism is a purely Lakatosian one. The concept of global reductionism within a physicalist framework gained a LOT of credence when about half of chemistry was successfully reduced to physics in the first half of the 20th century, then multiple major breakthroughs were made in cellular dynamics by reducing them to biochemistry. The physicalist presupposition of global reduction was dramatically PROGRRESSIVE, while the dualist and idealist frameworks that were competing with it at the time -- were REGRESSIVE vs all of these advances. Papineau explicitly states that neither dualism nor idealism were REFUTED, but they were outcompeted in effective utility. Physicalism was NOT the primary philosophic worldview in the first quarter of the 20th century, but by the 1960-70s, it was a significantly majority view.

The "refutations" of physicalism should therefore be in similar Lakatosian terms. Are there areas where physicalism has, or could, stall out and not be a useful methodology? The first place one should look for this is whether reductionism has continued to be so progressive. And the answer is -- definitely NO. The successful reductions of other sciences to lower tier sciences, basically stalled out in the 1960s. STILL only half of chemistry has been reduced to physics. And only some aspects of biochemistry have been reduced to chemistry. Basically no other science has had any major sub-area successfully reduced. This is spelled out in SEP's Scientific Reductionism article, section 5 -- reductionism remains useful, but GLOBAL reductionism -- is no longer considered feasible. And if not everything can be reduced to physics -- this is a fact which is a significant detriment to the claims of physicalism.

There are other empirical problems for physicalism. The Hard Problem of Consciousness is that physicalist models of consciousness -- would predict us not to be conscious. Yet we are. And parapsychology and non-western medicines keep passing statistically significant tests, and both are much better explained in either a dualist or idealist framing.

There are also multiple logic problems for physicalism. Physics cannot justify itself -- hence not all knowledge can be physics knowledge. Science is also not logically closed -- hence physicalism is undefinable in principle. This is Hempel's Dilemma -- any definition of physicalism that has content, is going to be refuted by example. And a significant minority of theoretical physicists think that physics is not our lowest reduction substrate, but that instead physics reduces to math -- which is an idealist framing.

These are not future possible problems, but current problems for physicalism, and none of them have shown any progress since the 1960s. Increasing numbers of philosophers have concluded that physicalism is regressive, such that the prior absolute dominance of physicalism has waned, and all of the alternative options have experienced renaissances of adherents.

Examples of major philosophers who have adopted non-physicalism:

  • David Chalmers: Parallelist dualism, with causal closure of both physics and mind. See The Conscious Mind.
  • Jaegwon Kim: former physicalist adopts epiphenomenal one-way interactive dualism for non-functional qualia only. See Physicalism or Something Near Enough.
  • Daniel Stoljar: Former physicalist abandons any ontology in favor of just using methodological naturalism, due to modern physics (QM and relativity) not being material, and Hempel's Dilemma. See Physicalism.

Physicalism remains the most widely held philosophic view, but the trendlines for the last half century are moving away from it.

  • The existence of other minds is also untestable. The proposition that the sun will rise tomorrow is untestable. The belief that we cease to exist after we die is untestable. To say that either of these things are unreasonable to believe in because you can’t test them is preposterous. You cannot even do science without axioms that are untestable. Commented Mar 9 at 20:59
  • @Baby_philosopher -- put downs of answers here is neither kind nor respectful philosophy.stackexchange.com/conduct Coping is the essence of wisdom and judgement, and is far superior to NOT coping. All of the above are testable, the concern you seem to have is that tests are not logically definitive. That is true of all testing, see Quine-Duhem. Testing, and a focus on testability, becomes a community attitude, not a logically specifiable practice. My answer explicitly details how both beliefs are reasonable, perhaps reread the wall of text?
    – Dcleve
    Commented Mar 9 at 23:51

Physicalism as described in the linked article is so underdefined that it doesn't make any claims at all to be true or false.

At best it's a commitment to investigate everything with the scientific method, in faith that doing so will be effective. Such commitments may be laudable, but can't be true or false.

At worst it is just somebody asserting a priori the conclusions of 19th century materialism, minus the now-falsified premise.

If we examine the proposed definitions in the wikipedia article, we can see that "physical" is sufficiently loosely defined that even substance dualists turn out to be physicalists. (This is not an especially big deal. Anybody can turn dualism into monism by drawing a circle around the two categories and calling the contents of the big circle the 'one kind of thing'.)

a property is physical if and only if it either is the sort of property that physical theory tells us about or else is a property which metaphysically (or logically) supervenes on the sort of property that physical theory tells us about

Cool. The Pope believes that God logically supervenes on the origins of the universe. Physics has theories about the origins of the universe. Therefore the Pope believes that God is physical.

OR: a property is physical if and only if: it either is the sort of property required by a complete account of the intrinsic nature of paradigmatic physical objects and their constituents or else is a property which metaphysically (or logically) supervenes on the sort of property required by a complete account of the intrinsic nature of paradigmatic physical objects and their constituents

Also cool. The Pope believes that souls are necessary for a complete account of the intrinsic nature of living human beings. Living human beings are paradigmatic physical objects - you can trip over them! Therefore the Pope believes that souls are physical.

I guess that settles it. How could any reasonable person disagree with God's vicar on Earth, his Holiness the Pope?


The definition includes things like structure, information and state as things "described by physics". This is wrong as none of these has any physical properties whatsoever.

Structure, information and state are thus not described by physics. Instead, they describe physical objects, they are physical properties themselves.

Physicalism as described in the Wikipedia definition is clearly false. Information, descriptions and properties of physical objects are not physical objects themselves.

  • 1
    That being said, one can claim that any information is necessary recorded on some physical media. This claim might be impossible to refute. Commented Mar 6 at 4:39
  • That is an obvious fact, not a claim. Information is always "recorded" on a physical object as information is a description of that object. Commented Mar 6 at 6:54
  • Are you sure though? Are you sure that the information recorded on some media always describes the media itself? Think a vinyl record, for example. Commented Mar 6 at 7:07
  • 1
    @PerttiRuismäki — in other words any physical structure describes itself. And if any information is some physical structure, then in what sense information is not physical? Commented Mar 6 at 13:33
  • 1
    @YuriZavorotny Physical structures don't describe anything. The music (=information) describe the record. Commented Mar 6 at 14:42

I think the answer of GS is along the right lines. We tend to use the word physical to refer to things that are tangibly real and fit within a scheme of scientific understanding that we have developed. Ghosts, for example, don't fit into that category. We have no well-developed theories about the properties of ghosts. We don't know how they could be visible, because to be visible they would have to generate or scatter light, and we don't know how light could be generated or scattered except by the physical phenomena. We don't know how ghosts move from place to place, how they can interact with physical objects (as poltergeists are supposed to) and what source of power they use to move physical objects, or how momentum and energy are conserved in such interactions, or where ghosts exist when they are not manifesting, or why a ghost's appearance should resemble the physical person they used to be, why ghosts are supposedly human-sized rather than microscopic or the size of a planet, why we don't see them all the time, etc etc etc. In other words, ghosts seem entirely unlike the rest of what we consider to be physically real, and as a consequence many people would take the physicality view that ghosts don't exist.

Now, suppose we did find evidence of ghosts, and find a way to fit them into our scheme of understanding, so we know how they scatter light, how they interact with objects etc. Would you say that proved physicalism to be wrong, or would you say that ghosts had now been established as having a proper place in our scheme of understanding of reality- ie they were encompassed in our definition of physicalism?

As for tests of what counts as reasonable... It's a vague word, and different people will have different views about what is and isn't reasonable. Generally it means consistent with the results of conventional reasoning, which you might take to mean the application of rational judgement to evidence. It would not be reasonable, therefore, to claim that the average height of people in Grimsby was nine feet seven inches, since that would conflict with accepted evidence. Nor would it be reasonable to hold two directly conflicting beliefs, since that would be irrational. Between those two clear-cut extremes, reasonableness becomes rather hard to pin down, largely because judgements requires competing factors to be weighted in some way, and that can be inherently subjective. I personally hold the view that it is not reasonable to believe in ghosts, god, etc, given all the reasons I listed earlier, but I would be open to changing my mind if suitable new evidence emerged.

  • "We have no well-developed theories about the properties of ghosts" -- suppose we haven't yet. But it doesn't mean that there isn't some real-world phenomena that can be perceived as ghosts. In fact, the belief is so long-standing and so widespread that it is not unreasonable to suspect that there could be something real behind those accounts. Commented Mar 6 at 7:00
  • @YuriZavorotny cheers! You've reminded me that I need to edit my question to say something about what reasonable means! Commented Mar 6 at 7:09
  • LOL, same here :) Commented Mar 6 at 7:12

The better question is probably: what does it mean for something to be "non-physical", and how would we know that such a thing exists. I see physicalism (whether metaphysical or methodological) more as a rejection of things that are "outside the physical".

A related answer of mine about what physicalism means:

People make all sorts of claims about the "spiritual", things that exist outside of space and time, and so forth. But they can't offer a concrete definition of what exactly that means and how such an existence would even work or interact with our observable physical reality, nor do they provide a reliable means to detect, measure, test or verify it.

Metaphysical physicalism is a rejection of all of that, until such a time when those questions have been sufficiently addressed for any given claim (at which point what it's claiming would arguably be considered part of physical reality).

Also related: Is naturalism falsifiable?:

If we cannot demonstrate supernatural claims (perhaps because our definition of supernatural is very closely tied to not being demonstrable), then naturalism cannot be falsified, but also shouldn't be falsified, because it's rejecting claims that cannot be demonstrated.


One could certainly conceive of a device that would allow us to clearly observe ghosts or other supernatural entities. One could also conceive of natural explanations for this, e.g. what we're observing may just be sufficiently advanced technology or natural phenomena we don't yet understand, but many people may nonetheless deem this to meet the burden of falsification, be sufficiently convinced of the supernatural and abandon philosophical naturalism. But the bigger question is: if we can clearly observe ghosts, would they still classify as supernatural? Opinions would probably be divided on this, and it's a crucial part of whether philosophical naturalism is and should be falsifiable.

For someone to argue that non-physicalism is reasonable, I'd say they'd need to argue for a better metaphysical or epistemological framework.

What does "better" mean? I'd measure that in terms of reliability (how often you're correct) and consistency (treating everything the same unless you have good reason not to). The importance of those things are hopefully self-evident, but that's not prescriptive: someone can make a case for whatever criteria of "better" they want. Other people would accept it if they deem that criteria to be reasonable.

I don't know that there is much to say about the reasonable-ness of "non-physicalism" in general.

Is non-Newtonian gravity reasonable? Well, yes, and that's general relativity. But one wouldn't argue for non-Newtonian gravity in general as much as one would argue for general relativity above Newtonian gravity. Without general relativity, and without specific demonstrable examples of where Newtonian gravity fails, non-Newtonian gravity is not reasonable.

That may not be a perfect analogy, but it hopefully shows the issue with thinking in terms of "is something-that-isn't-that reasonable".


Reasonableness. What does it mean for a position to be reasonable? What conditions does a position have to meet to be regarded as reasonable?

Reasonable just means that your position is logically derived from true assumptions.

There are two main difficulties, though.

First, most of the time, we don't seem capable of making explicit our reasoning in such a way as to prove to others that it is logical.

Another recurrent difficulty is that premises which may seem obviously true to us may not be to other people, and we may be unable to justify them logically from more basic premises which would be obviously true to others.

In philosophy, physicalism is the metaphysical thesis that "everything is physical", that there is "nothing over and above" the physical, or that everything supervenes on the physical.

Physicalism as defined here is not reasonable as I just defined reasonable.

Physicalism is not reasonable because nobody seems able to explain, at least for the time being, our own subjective experience in physicalist terms.

Thus, non-physicalism can be understood as the thesis that physicalism is false, that is, the thesis that not everything is physical, or that there exists at least one thing that is not physical.

Is the belief in non-physicalism reasonable?

Not for the time being at least. It doesn't seem that anyone can argue non-physicalism from obviously true premises.

  • 2
    So, are you saying that both physicalism and non-physicalism are unreasonable? Should we be agnostics on this issue?
    – Mark
    Commented Mar 6 at 18:04
  • @Mark At least for the time being and only as far as I know. We don't even seem to have a clue. Commented Mar 7 at 10:28
  • I would agree with the last sentence only if the premise "there is such a thing as truth" is not an obviously-true premise.
    – Matthew
    Commented Mar 7 at 17:21
  • @Matthew I have no idea what you mean. Commented Mar 7 at 17:42
  • The "we do not know" approach is... reasonable, but "reasonable" does not mean "logically derived from true assumptions": this is simply true. Reasonable, that is what we can achieve, at most, in philosophical debates, is something like: well-argumented, devoided of contradicitions, without blatant contentions with known facts,... Commented Mar 8 at 10:10

Is the belief in non-physicalism reasonable?

If you could get a reasonable answer to this question, we would be living in a world where the topic of religions has been resolved one way or another. You cannot.

If you believe in something, then the belief is reasonable to you. If you do not, then it is not. There is nothing more to it, when speaking in plain language. This is not a question of the subject matter of your belief, but about the very concept of "belief" itself.

The SEP has a lot to say about what it means to believe. Not only regarding religions or other "big" concepts, but also on the very mundane levels.

I believe there is a coffee cup next to my left hand on my table. You can do nothing whatsoever to change this belief, no matter how hard you try. Also I can do nothing whatsoever to make you share my belief reasonably. If we cannot even agree about my coffee cup, how would we reason about concepts that are (by definition) not visible, not measurable and in no way, form or fashion distinguishable from fantasy?

How can someone reasonably conclude that physicalism is (probably) false?

You cannot. Belief systems are outside of the realm of "concluding". You have science for everything regarding physical stuff (by definition) and philosophy for everything we humans can think about, so most importantly, abstract concepts. For the rest (gods, spirits, souls, fairies and so on and forth - i.e. all that dualism or pluralism would add) we have pre-existing belief systems which are transmitted to future generations by way of humans writing/talking about them.

Is there any piece of data that might lend credence to the rejection of physicalism?

No. If there were, you would not be asking the question. You can be sure that if there were some piece of data which would make dualism seem inevitable to skeptics (scientists, philosophers without a-priori-beliefs), we would all know about it. It would be the single most explosive piece of information humankind would ever have been privy of, it would be utterly impossible to keep secret or avoid that even the last human living in some hut on a mountain would sooner or later learn of it.

This is of course only true if by "credence" you mean "incontrovertible fact, open to review by scientists and philosophers of all beliefs, including strict atheists and physicalists". Obviously there are a great many people who believe all kinds of things, and to those, everything they believe in has, by definition, credence; so they by definition must reject physicalism.

  • No. If there were, you would not be asking the question. You can be sure that if there were some piece of data which would make dualism seem inevitable to skeptics (scientists, philosophers without a-priori-beliefs), we would all know about it - Do you have a hypothesis then as to why about 50% of philosophers are not physicalists? (See this answer for the statistics. Or simply click here survey2020.philpeople.org/survey/results/4874)
    – Mark
    Commented Mar 8 at 11:25
  • @Mark, there can be plenty of reasons for a person to subscribe to dualism or pluralism (maybe even the slight hunch that physicalism simply "cannot be all there is to it", or being brought up with religion, etc.). But you have asked for a "piece of data". I interpret "piece of data" as something objectively measurable or "showable", anything that is not only belief-based and that "works" for someone who does not already believe in it. Note that I make no claim about whether physicalism is true or false in my answer (at least not intentionally).
    – AnoE
    Commented Mar 8 at 12:29
  1. A philosophical position is reasonable if is based on rational arguments. The position takes into account the knowledge of the time and derives its argumentation in a logical way.

  2. According to your quote physicalism is the claim that physics encompasses and explains everything, because you enclose not only physical objects, physical processes but also mathematics, morality, intentionality.

    To me it seems that these exaggerations construct a straw man, which can be easily ridiculed and therefore rejected. That’s not the basis for a philosophical dispute about the achievements from science and humanities to explain the phenomena we observe in our world.

  3. IMO thinking according to such bold categories like physicalism and non-physicalism - which some would call idealism - is outdated. These concepts carry the burden of a long tradition which knew less in comparison to current knowledge. There exist better classifications like Popper’s "Three Worlds", for an introduction see Popper's Three Worlds.

    Caveat: As always, stereotyped thinking can only serve for the first orientation.



Not only is non-physicalism reasonable, physicalism is, by its own definition, not reasonable.

Reason and logic are immaterial. While there is dispute whether the process of applying logic and reason contains any immaterial component (and it's worth noting that the arguments on that point, on both sides, are largely and to some degree necessarily circular), if "logic" and "reason" are strictly physical processes, the very nature of what they purport to be is undermined. Put differently, there is no purely physicalist reason to suppose that these processes are in any way accurate representations of reality.

The Problem, Restated

Several questions are asked:

  • What conditions does a position have to meet to be regarded as reasonable?
  • "Is the belief in non-physicalism reasonable?
  • How can someone reasonably conclude that physicalism is (probably) false?
  • Is there any piece of data that might lend credence to the rejection of physicalism?

The best answer I can give is that a position (at least, of the sorts of positions we're discussing) can only be reasonable if it serves a purpose; that is, if it has superior explanatory power. Inherent in this is that a position's reasonableness is directly proportional to the unreasonableness of another position, at least to the extent they are mutually exclusive.

Belief in the Flying Spaghetti Monster is not reasonable on two fronts; first, it does not offer superior explanations to anything we observe or experience, and second, because there is no external evidence of such existence.

The take-away point here is that all of these questions are interrelated. A position which posits something other than pure physicalism is reasonable if it has superior explanatory power than physicalism, which is the same as saying that physicalism's explanatory power is inadequate (and thus, pure physicalism is "probably false" and ought to be rejected). Thus, in a sense, it is only the last question that needs to be answered.

It's worth noting that what we're asking here is very similar to the Question Is materialism essential to scientific progress?.

Cosmological Fine Tuning

The first objection to pure physicalism is the fine tuning problem. In short, the number of extremely precise coincidences that need to occur for life to exist is such that it is not reasonable to conclude that "we just got that lucky". The traditional response to this problem is Intelligent Design; that is, that some factor which cannot be accounted for by physicalism is manipulating the outcome such that the result is a matter of planning rather than chance.

There are two traditional attempts at rebutting this position. One, the puddle analogy, either implies the second method, which we will visit in a moment, or assumes that intelligent, reasoning life is a necessary outcome of any possible set of starting circumstances. However, so far as we know, it isn't that life as we know it isn't possible under other conditions, but that life of any kind isn't possible. To refute this, one would need to show not only that life could exist in a different cosmology, but that every cosmology is likely to produce intelligent, reasoning life. To my knowledge, this has never been done. (See also this question for further discussion.)

The second "escape hatch" is to assume an infinite multiverse; that is, every cosmology that could exist, does exist, and those that don't support intelligent, reasoning life simply lack philosophers to argue about the meaning of it all. However, this assumption is rooted in circular reasoning; the only evidence we have of this "multiverse" existing is that we're here, and that we have chosen, on philosophical grounds, to exclude other possible explanations. Additionally, an argument could be made whether this unobservable and inaccessible "multiverse" still constitutes "pure physicalism".

Living Organisms

The problems with explaining life in purely physicalist terms are so severe that even some physicalists object to existing explanations. I don't want to turn this into a debate over Intelligent Design, but the facts are that what we observe is more consistent with the actions of an intelligent agent acting to create, or at least direct, the life that we see around us. Life uses encoded information, the only demonstrated source of which is intelligence. Life, as with man-made artifacts, is full of homology, or the use of similar features for similar purposes made in disparate manners. Experiments and observations strongly indicate that biology tends to a state of increased entropy (consistent with the second law of thermodynamics); minor gains are possible, but on average are substantially outweighed by losses. Rapidity of diversification is not consistent with changes accrued by chance processes; rather, such rapidity would seem to require either acting on existing biological information, or enormous quantities of information being "injected" by an external source.

As material science has not been able to identify the source of biological information, it cannot be categorically ruled out that said source is itself material; however, if it were, the questions of the ultimate source of biological information merely get "kicked down the road". An immaterial source does not suffer from these deficiencies, and therefore has superior explanatory power. Moreover, there might be historical indicators that point to the nature of this source.

As with the previous section, this points to something non-physical providing superior explanatory power than pure physicalism.


I'm going to ignore questions like Is knowledge non-physical?. At a glance, the existence of knowledge, math, logic and so forth could be argued to negate pure physicalism all on their own. Still, this seems like a technicality.

Related, however, is the problem of consciousness, which seems to elude explanation in strictly material terms. The implication here would seem to be for some sort of "spirit" or "soul". Contrary to some other claims that have been put forth here, this is usually believed to be immaterial, and their ability to interact with the physical world limited, perhaps via the mechanism of nervous systems. Although some behaviors (e.g. flocking) seem to have succumbed to purely material explanations, others, such as the complexities of bee communication, seem to challenge the physical limits of anatomy. (Personally, I have often wondered if Orson Scott Card is on to something with his idea of "philotes".)

Morality and Spiritualism

Another complication deals with the fields of ethics and morality. If pure physicalism is correct, there is no underlying cause to believe that our perceptions, or especially our logical faculties, are accurate, yet this assumption seems prevalent. Further, most humans believe that certain things constitute absolute truths, and that certain things are "evil", whereas the very concept of "evil" is nonsensical to pure physicalism.

Most humans also seem to instinctively seek "meaning" in life (beyond "reproduce your genes"), and we seem to have an innate desire for "the spiritual". While adherents of pure physicalism insist that these are not insurmountable difficulties, they are nevertheless challenging. More importantly, however, they are extremely consistent with, or even expected of, a position that is not pure physicalism.

Jesus of Nazareth

I don't usually like to promote specific religions in this sort of question, but the specific case of Jesus of Nazareth plays directly into the subject matter. What we know, historically, is that:

  • A man named Jesus, being from the town of Nazareth, existed and lived around the time 0 AD - 30 AD (give or take a few years).
  • The same man was executed by crucifixion on the order of a Roman official named Pontius Pilate around 30 AD.
  • Jesus body went missing and could not be located.
  • At least a half dozen — and probably hundreds or more — people subsequently claimed to see Jesus alive. None of these claims were repudiated under torture.
  • These events ultimately resulted in the creation of one of the most popular religions in all of history.

I repeat that these are facts; no competent scholar claims otherwise. Nor are these facts attested to only by those writings part of what is popularly known as "the Bible". Note also that the above list does not include "Jesus actually rose from the dead". That is an inference, and, while other explanations are suggested, it remains the most plausible inference given the above facts.

This is relevant for two reasons. First, because it strongly suggests an occurrence that cannot be accounted for by pure physicalism. Thus, it serves to answer the question in demonstrating the falsity thereof. Second, because it suggests that this "Jesus" may possess unique (or at least uncommon) insight into the non-physical realm, and that therefore His claims with respect to the same — and perhaps, by extension, claims made in earlier writings that predicted the events of Jesus' life, death and resurrection — are more credible than other claims regarding the non-physical. That is, this singular event can help us not only determine that pure physicalism is false, but can help us narrow down what specific alternative is most likely to be true.

There are, of course, other religious claims that can also be considered. However, the Resurrection stands apart in terms of the quantity, quality, diversity, and immediacy of its historical attestation.

  • Regarding the last piece of evidence, this may be relevant.
    – Mark
    Commented Mar 7 at 20:44
  • Regarding morality and physicalism, this may be relevant.
    – Mark
    Commented Mar 7 at 20:45
  • Regarding consciousness, this may be relevant.
    – Mark
    Commented Mar 7 at 20:48
  • @Mark, most counter-arguments (and, indeed, materialism itself) have a substantial basis in circular reasoning. Considering the Resurrection, for example, what's the best explanation? According to the materialist, a material explanation is better. What is it that makes it better? It's better because it's a material explanation. Logic and reason don't play a part here; it's dogma all the way.
    – Matthew
    Commented Mar 7 at 21:10

To my opinion, this question cannot be answered in a totally convincing, irrefutable and generally accepted way. This is quite evident, since otherwise it would not be so popular. In fact, tt would not have survived! 🙂

The reason for this is that physicalism is a theory, a philosophical system, a worldview as any other. They are all subjective in nature. As is the word "reasonable", which to my opinion has not much meaning or usefulness here.

So, what one can do is to present an argumentation showing that physicalism is imperfect or defective, well, in short reject it! 🙂

And this is what I will do.

If --according to physicalism-- everything is physical, then everything could be perceived by our senses --not only the 5 basic ones but any of the about 50 senses that are known. This would also include, e.g. thoughts. Can they be perceived by our senses? Obviously not. We can only be aware of them. We can only be aware. And thoughts. Some scientists --esp. among the hardcore and arrogant ones-- would insist --without any substantial evidence whatsoever-- that these can be detected as products of the brain (which BTW, they identify with the mind). We can add dozens of things that are not physical and still we know well that they exist, because we

Besides, nothing pertaining purely to the mind, like thoughts, are mentioned among the things that physicalism encompasses, as described in the excerpt from Wikipedia that is brought up. But I guess in none other reference, as far as I know.

The above is only one way to show that physicalism cannot really encompass everything. Therefore, it is a defective philosophy.


How can someone reasonably conclude that physicalism is (probably) false?

I don't think it is possible. Even if we haven't yet discovered the physical process driving some observable patterns (our consciousness, for example), we can never claim that such a process does not exist -- or that it will never be discovered.

Therefore, we must conclude that non-physicalism is not reasonable.

UPDATE: Some commentators pointed out that the argument above is incomplete — and that’s true because it does not clarify what “unreasonable” means in this context. So I’ll add this part.

The reason for holding any beliefs whatsoever lies in their actionability. In other words, there is no point in holding a belief that is not actionable. That’s why it’s unreasonable to believe in unicorns — because what are we going to do about it? Same with declaring than some observable phenomenon, like consciousness, is caused by a non-physical process — it’s possible, all right, but then what? What such an assertion achieves, aside from requiring us to stop looking for a possible physical cause?

This is what makes non-physicalism unreasonable: It tells us to stop being scientists. To stop searching for the truth.

  • 4
    I'm not quite following. You say it's not possible to conclude that physicalism is false, therefore non-physicalism is not reasonable? How does that follow? What if there is some non-physical cause? Our inability to conclude that it couldn't have been physical doesn't automatically mean that it's not reasonable to accept that there's a non-physical cause. The argument seems to be something like "this is unfalsifiable, therefore anything that isn't this is unreasonable", but that also works for deities, unicorns, you being a brain in a vat, etc.
    – NotThatGuy
    Commented Mar 6 at 5:57
  • @NotThatGuy -- I think you have answered your own question :) Non-physical causes are like unicorns -- and we have no reason to believe in either. Commented Mar 6 at 6:42
  • Of you course one can always claim that for them it's not unreasonable to believe in unicorns. And we cannot argue with that. Only the person themselves can decide what is reasonable -- for them -- and what isn't. Commented Mar 6 at 6:49
  • YuriZavorotny The structure of your argument is "if X is unfalsifiable, then not-X is unreasonable". What @NotThatGuy rightly pointed out is that there are many values of X that would satisfy the IF part of your argument, namely, Cartesian evil demons, the Matrix, solipsism, the universe was created 5 seconds ago, many deities, undetectable universes, etc. The structure of the argument commits you to believing that, for instance, the belief that the universe was NOT created 5 seconds ago is unreasonable.
    – Mark
    Commented Mar 6 at 13:30
  • @Mark — you both are correct, I skipped a step in my reasoning. Specifically, I did not clarify what “unreasonable” means in this context. Commented Mar 6 at 13:39

No, it isn’t. The only non physical things that we know of that exist are subjective mental states. But we know for a fact that our physical brain remains intact even when those mental states vanish such as during sleep.

On the other hand, there is no evidence whatsoever of mental states existing without the brain. This suggests that they supervene on them.

Non physicalism is cope from wishful thinkers who want to go against the brain and disbelieve the most obvious and parsimonious truth that we cease to exist completely and utterly when we die


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