Physics and biology have no answer why or how we personally experience the color red and we say that the experience of the color red is a quale.

Physics also has no answer why or how we experience the flow of time. So is the experience of the flow of time also a quale?

Since the flow of time is so closely related to cause and effect (i.e. the cause cannot come after the effect), is our experience of cause and effect also a quale?

  • I would answer No to this question. Qualia are generally understood to be irreducible, instantaneous experiences. The flow of time is evident to a human only because things change from one moment to the next. It is not a specific quale. May 30, 2023 at 23:02

3 Answers 3


Yes, the flow of time is exactly of the nature of a qualia, but I dispute the idea that physics has no answer about how or why we experience it. The thing that one must accept first is the physicist's positivism: once you answer every question about the measurable attributes of the brain and behavioral states, you have given the answer all questions about the qualia, even though the map between the qualia categories and the measurable attributes might be complex.

The theory of mind that physicists usually accept without reservations is the computational theory of mind, which was proposed by Alan Turing in the 1940s. The computational theory of mind begins with the observation that a computer can simulate the behavior of any physical system, including a human being, and then makes the positivist claim (this shouldn't even have to be said) that if you have something behaving indistinguishably from a conscious person, it is a conscious person. Turing codified the positivism in the Turing test--- if the communication with the computational entity is indistinguishable from the communication with a person, one identifies the computational entity as a conscious thing, like a person. This is common sense, and it is not something I consider worthy of reasoned debate.

The computational theory of mind identifies the flow of time with the direction of the computation, the relation between inputs and outputs. In any physical computer, the computation must dump heat into the environment in order to keep its information from randomizing, so for a regular computation in time, this is the same as the entropy arrow of time. The identification of the entropic and conscious arrow of time follows.

The "feeling" of time passing is a high level property of the brain's computation, and it is a property of the software, or the mind, or the soul, I use all these terms interchangably because they are equivalent in the computational view. The software is abstract data, and the manipulations of this data can be described using larger qualia, which are just shorthands for classes of data stored in the software.

The embedding of the software into the physics matches the conscious time sense with the physical time sense. The main complicated stuff is in the software, not in the laws of physics. That the flow of time is not physics is manifested by its dependence on the mental state of the observer--- having a traumatic experience requiring immediate action, taking hallucinogenic drugs, falling ill, each of these can change the perception of time in drastic ways.

The feeling of time flow is so universal, and the changes in this flow in unusual states is so jarring to the individual, that many people look to physics for confirmation of the feeling that time is something fluid and unreal. They find false confirmation of this in relativity (which has nothing to do with the essentially nonrelativistic events in the brain's computation) and string theory, and this makes these topics more popular than type II superconductors, although these are equally interesting and both are about equally relevant to consciousness.

Anyway, the person who removed time flow from physics explicitly and put it into the mind is Ludwig Boltzmann, and once he did so, he was able to ask questions about Boltzmann brains. The concept of a Boltzmann brain (a brain emerging fully formed from a thermal state by a fluctuation, and feeling continuity with previous experience vastly removed in physical time) requires a separation of the sense of cause and effect or of time from the laws of physics. This is standard physics philosophy, it reappears in the many-worlds interpretation, which is controversial for reasons that have nothing to do with its computational theory of mind.

  • Where did Turing propose a computational theory of mind? Where did he claim that "a computer can simulate the behavior of any physical system"? Where does Turing codify whatever you wrote there in the Turing Test? He proposed The Imitation Game as a replacement to the question "can machines think?" and regardless, qualia and consciousness are arguably different from thinking or its imitation; consider this excerpt from that paper "I do not think these mysteries [of consciousness] necessarily need to be solved before we can answer the question with which we are concerned in this paper".
    – nir
    Mar 5, 2015 at 20:00
  • 1
    @nlr: If Turing disagreed, great, it's mine! But he didn't. The computational theory of mind is attributed to Turing in his 1940 paper introducing the Turing test. The statement that a computer can simulate an arbitrary physical system is implicit in the Church-Turing thesis of 1936 and clearly motivates the 1940 proposal. The imitation game is not a replacement for the question "can machines think?", it is the best precise positivist formulation. The point of the Turing test is that "qualia" and "consciousness" are there, you can't imitate consciousness without getting the internals right.
    – Ron Maimon
    Mar 6, 2015 at 8:42
  • @nlr: The "mysteries" of consciousness are not mysteries when you understand the mysteries of computation, as it's the same mystery. Turing might have had the completely wrong idea that a machine can pass the Turing test by trickery, by fooling you into thinking it has imagery and mental states, and memory and dynamic updating of its mental state, just by doing syntactical manipulations without a full internal representation of a human-type awareness. This idea is clearly incorrect. Since he never explicitly says that this is possible, I assume he wasn't so stupid, but I don't care about him.
    – Ron Maimon
    Mar 6, 2015 at 8:45
  • you wrote that the computational theory of mind is attributed to Turing, and I ask again out of interest, (and since I believe it is wrong) where and by who? why is your statement about simulability of physical systems implicit in the Church-Turing thesis? if by a physical system you mean a mathematical description that can be computed effectively, then that is true, but is it interesting? if on the other hand, by physical system you mean something in the real world, which our physics is meant to approximate, then the question seems to remain open, isn't it?
    – nir
    Mar 6, 2015 at 14:08
  • as for consciousness, I do not agree it is the same mystery as computation; while it might be possible for a computer to simulate human psychology, cognitive processes, and behavior, I believe the so called qualia is something different than these things, which is out of reach for Turing Machines; I admit that from my experience most intelligent people either in physics, computer science or philosophy reject that position; however, I cannot reconcile their view with my inner experience, and I suspect that they are using the same words to describe their own inner experience, not mine.
    – nir
    Mar 6, 2015 at 17:10

When looking at an ambiguous image of a cube (the Necker cube), there is something it is like to interpret it as a cube that you're looking down on, and there is something it is like to interpret it as a cube that you're looking up to. There's also something it is like to not interpret it as a cube at all, to just see a collection of lines or pixels. The first two experiences involve some higher-level interpretation of the raw sense data, relying on an internal three-dimensional model of the outside world. One might argue that perceiving the flow of time, or cause and effect, is similar -- there is something it is like to have this experience, but we do not perceive the flow of time or cause and effect directly in our sense data, just as we don't experience the three-dimensional nature of space directly through our vision. The experience relies on interpretation using some internal model of the outside world.

Not everyone is likely to agree with this though; in particular, I believe some A-theorists have argued for the A-theory of time based on the direct experience of the flow of time.


No, our experience of the flow of time is not what is meant by a "quale". Our experience of the flow of time is in fact a series of different experiences that could be anything, so our experience of the flow of time is tantamount to consciousness itself. Whereas a quale is a specific perception: of light, of sound, of taste, of touch, etc.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .