I do not understand how, without understanding the mind and how (physical) neural interactions within the brain give rise to consciousness, one can have a definitive theory of everything. There will always be the unsolved problem of how physical processes give rise to subjective experience. However, when talking about the TOE, consciousness is rarely discussed. Why is this?

If I may also add, I was conflicted as to whether or not I should post this in Philosophy.SE, but I decided to post this question here since the TOE is a problem in physics.

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    $\begingroup$ Short answer: It is commonly accepted that things like "conciousness" (whatever that may mean, exactly) are emergent phenomena, i.e. things that do not appear on the smallest, fundamental scales. Instead, they arise due to complex interactions of many smaller systems, particles or whatever other building blocks we may propose. Therefore, one does not typically bother to even consider these things when trying to understand the fundamental constituents of the universe. $\endgroup$
    – Danu
    May 6, 2015 at 19:10
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    $\begingroup$ "Theory of everything" is a misnomer. The term refers to the reductionist idea of a fundamental description of reality, from which in principle all observable phenomena could be explained (but definitely not in practice!). It is not literally an explicit explanation of every observable phenomenon, such as consciousness. Nor does it need to be an explanation of the existence of observable phenomena/subjective experience. In fact it should be pretty obvious that no such non-circular explanation could exist. $\endgroup$ May 6, 2015 at 19:14
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    $\begingroup$ @MarkMitchison: I believe that is the answer, not merely a comment - OP has misunderstood what a "TOE" is supposed to be. $\endgroup$
    – ACuriousMind
    May 6, 2015 at 19:31
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    $\begingroup$ And it is a mistake we've seen reflected by questions (mostly poorly written) on the site before. Often from correspondents who wouldn't accept that the answer could possibly be so simple. I mostly blame the science media for that: stories get printed if they are exciting and revolutionary rather than measured and judicious. $\endgroup$ May 6, 2015 at 19:59
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    $\begingroup$ So far I have not even seen a useful definition of "consciousness"... $\endgroup$
    – CuriousOne
    May 7, 2015 at 2:18

4 Answers 4


The question is a possibility on both sites; though on Phil.SE you're more likely to get a wider range of answers.

If one accepts the physicalist view then mind is said to be an emergent phenomena as @danu mentions; but a more careful view suggests that bulk properties as heat are emergent - in that a definite physical mechanism can be shown ie through statistical mechanics; but given no physical mechanism has been shown for minds; the more acceptable possibility is to say mind supervenes on the physical world; this accepts that minds are natural kinds.

There are other positions such as panpsychism, which derives from Democritean 'soul atoms'; or various kinds of Neoplatonism from Plotinus, Mulla Sudra and Spinoza (one might call these supernatural positions, if it wasn't got the occult connotations); they are also named as Emanationist theories; Leibniz developed a hybrid theory between these two positions which he expounded in The Monodalogy.

Chalmers book on The Philosophy of Mind is a good place to look; as well as the IEP and SEP.

To answer your headline question - theories of everything, to my mind is in part an expression of the hoped for union between GR and QM; and that is seen as a final theory; and perhaps in part, an expression of the (minority) physicalist view saying all that is - is matter (sensible or insensible ).


Your question is a valid one and the missing piece of information that both answers your question and justifies the study of physics itself is a reductionist postulate to the effect that valid explanations of the most basic and most decomposed parts and behaviors of a system can be built into an explanation for all the system's behaviors and emergent phenomena.

Let's see what that means with the practical example comprising:

  1. On the one hand, quantum electrodynamics, which is what physicists think of as a theory of everything as far as the electromagnetic interaction is concerned;
  2. On the other hand, the patently true observation that a gecko can effortlessly walk upside down from a perfectly smooth glass ceiling, bearing its whole weight with whatever interaction it uses to stick its feet to surface. Indeed, almost any kind of surface, no matter how smooth, presents no problem for the gecko. The gecko can switch this reliable interaction on and off at will to lift his or her feet or arch the forward half of its body away from the surface to snatch and gobble up a passing flying insect, all the while its hinder half is anchored soundly to the surface by its hinder feet. Almost certainly there are no secretions of any kind of "glue" involved.

We postulate that what we are seeing in the case of the gecko is an quantum electrodynamic interaction - a van der Waals force - between nanometer scale hairs on the gecko's feet and the anchoring surface. What evidence do we have for this?:

  1. It seems plausible;
  2. We have partly replicated the effect in synthetic materials and theories of polarizability of molecules in the presence of their neighbors - a QED effect - seems to be an effective way of developing this technology;
  3. We have no evidence that there is anything other than an emergent phenomenon from the basic QED interaction involved;
  4. So we apply Occam's razor - the physicist's pragmatic resource management doctrine that says you don't spend resources chasing down a more complicated explanation unless you really need to.

But actually proving we can get a mathematical description of the gecko foot system beginning with basic QED calculations and building them up into a complete description of this particular emergent phenomenon: that is another matter altogether. Actually applying the theory of QED to a description of the interaction of tens of molecules already poses a mathematical problem that is intractable as yet either to our theorists or computing resources.

So, even though we can't as yet give a full QED description of the gecko's feet, I don't think that there would be many physicists around who would seriously think that this would not be something that could in principle be done. And the same goes for many nano- and micro-scale phenomena which are too complex for our basic theories but too small for simple continuum mechanical descriptions to emerge. Even if humans won't have the computing resources to fully describe the gecko's feet from QED for the next hundred years, we still believe that it can in principle be done.

Likewise for a TOE and consciousness. One can get to a stage where one believes that one has a description of the basic interactions and behaviours of the World which everything else - all behaviors including consiousness - emerges from and could be described in terms of - in principle - even though one cannot handle the complexity a TOE description of the emergent behavior.

Compare your question to the highly analogous Church-Turing thesis of the field of computability and foundational mathematics. This is a postulate or hypothesis or dogma made that, through the abstraction of the Turing machine, we understand the foundation for everything that can possibly be computed in principle by conscious humans, even though we cannot at this time know what every future human may be able to reason.


TOE is supposed to be a theory that explains everything microscopically, on the smallest and most fundamental levels. It doesn't bother with consciousness because that is a macroscopic phenomenon. Theoretically, with a TOE, we can explain consciousness, but in practice it would still be difficult.

  • $\begingroup$ Your statement that with a TOE, it is possible to explain consciousness even theoretically is non trival and is exactly the point of hard problem of consciousness. $\endgroup$
    – Razor
    Jan 14 at 22:00

To move forward with just about anything we must first need to take the leap that reality exists independently of our mind. This is something that we can, by definition, never prove one way or another, but since we cannot travel down the "reality is a dream" road, it only makes sense to go down the road that we can actually explore.

Getting past that, there's the idea that consciousness is a product of reality, and reality is a product of consciousness. This basically means that consciousness is nothing special, it's just a natural happenstance of how things happened to pan out. It does sound ludicrous to say that consciousness could quite easily have never occurred but the chain of logic is quite convincing that reality existed as it does before consciousness was created, and that "consciousness" is a gradual progression of rational events.

Our perception of reality however is based completely on the image that our brain creates given the various pieces of information it receives from our senses. Does that mean the reality is dependent on consciousness? No, it simply means that reality as we know it, may not look like what reality actually it. It will always be analogous on some level given that the image our brain conjures is based off of parts of reality that are definitively different than one another, but who really knows if these distinguishable characteristics that our brain is capable of recognizing result in a reality that is identical to the one we perceive.


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