Can consciousness (qualia) cause detectable and measurable effects? For example, would we able to tell the difference between a robot that experiences qualia vs. a robot that doesn't, by detecting the effects of qualia in the robot that has them?

If qualia do cause measurable, detectable effects, do these effects offer survival advantages from an evolutionary standpoint? I'm thinking of the standard naturalist account of the origin of life on Earth: Big Bang -> Solar System formation -> primitive Earth -> Abiogenesis -> Evolution. If qualia produce effects, was there a specific mutation (the qualia mutation) in the last step (Evolution) that caused an organism to experience qualia, offering it a survival advantage over other organisms that didn't?

  • @tkruse Rebuttal: 1) The word "human" is never mentioned in the entire question. Instead, the concept mentioned is "life on Earth". That encompasses everything that matches the definition of "life" (on Earth). 2) Do you reject any of the 5 steps mentioned? Do you reject the Big Bang? Do you reject the formation of the solar system? Do you reject the existence of a primitive Earth? Do you reject abiogenesis? Do you reject evolution? How is this a strawman?
    – Mark
    Commented Nov 23, 2023 at 16:50
  • @tkruse 3) "last step" refers to Evolution as a whole. I never said "the last step of Evolution". Instead, I said "the last step (Evolution)", meaning that I'm using both expressions as synonyms (evolution is the last step of the 5 steps I had previously listed, it comes after abiogenesis).
    – Mark
    Commented Nov 23, 2023 at 18:35
  • @tkruse There had to have been a point when there was a transition from a "no quale" state of affairs to "there is at least one quale" state of affairs. From zero to more than zero. Think of it like this: there had to have been a first organism that experienced the first quale. All organisms prior to it didn't have qualia. So there had to have been a mutation that was "the straw that broke the camel's back", causing the first quale to exist.
    – Mark
    Commented Nov 23, 2023 at 19:13
  • @tkruse Regarding your finding the use of the word "step" overloaded and problematic, feel free to replace "step" with "stage" in your mind, if that helps to alleviate your discomfort.
    – Mark
    Commented Nov 23, 2023 at 19:16
  • @tkruse But, again, if at time t1 there is no quale, and at time t2 > t1 there are many qualia, by sheer logic we know that there has to be a time t* such that t1 < t* <= t2, in which the first quale appeared.
    – Mark
    Commented Nov 23, 2023 at 20:17

3 Answers 3


There are many views on what consciousness is, and what its relation is to causation.

Regarding observable differences between conscious and non-conscious entities, there is the idea of philosophical zombies, which can behave and appear indistinguishably human, yet remain without consciousness.

There are 4 views one can take on this:

  • Philosophical zombies cannot exist because consciousness exists distinct from material reality and something without consciousness cannot behave or appear indistinguishably human.

    This does not seem to be a particularly popular view, and recent advances in AI is adding doubt to the idea that human behaviour cannot be simulated. There seems to be this back and forth throughout history where people would say "computers will never be able to do this thing", and then computers do that, and then they move onto some other things computers will supposedly never be able to do, and the situation repeats. The Turing test was proposed as a way to distinguish humans from computers, but chatbots don't seem that far off from being able to convince humans that they're human - in fact, there are already people saying ChatGPT feels so human (even if it still frequently repeats itself, confidently claims falsehoods as fact, and can say complete nonsense... which could also be said of some people).

  • Philosophical zombies are possible.

    Although if they can behave and appear indistinguishably human, one might posit whether there is any difference them and humans, with respect to consciousness, i.e. that either both have consciousness, or neither does.

    This view makes consciousness entirely unnecessary to explain anything in the world, beyond one's own conscious experience (and one might ask what exactly this thing you're experiencing is, and how you know who or what else is or isn't experiencing something similar, when the very premise here is that you cannot distinguish).

  • Philosophical zombies cannot exist because behaving and appearing indistinguishably human means you have consciousness.

    This would be the reductionist view: that a mental state is reducible to nothing more than firing of neurons and the chemical soup in your brain. Anything with an identical physical makeup would be conscious.

    Regarding AI and things with different, but functionally equivalent, physical make-ups, reductionists would presumably typically/always take the view that such things can theoretically be conscious too. To reject this under reductionism, there would need to be some physical differentiating criteria.

    Functionalism (the idea that a mental state is constituted solely by its functional role) tends to be interpreted similarly, but there are functionalist theories that say otherwise.

  • The eliminative view that what we think of when think of consciousness doesn't actually exist.

    Note that this doesn't mean that humans don't do human things, but rather it challenges how we label things, and it suggests that when we say "consciousness", some part of what we're describing doesn't actually exist. The rest, generally speaking, corresponds to neurons firing. This makes it very similar to the reductionist view.

The reductionist position fits well with evolution:

  • Human consciousness is the result of the complexity of our brain, and increasing brain complexity over time (something we have strong evidence for) offered a survival advantage, given that every additional neuron corresponds directly to increased mental capacity. But our brains also use a ton of energy, which is a huge downside if you still have a daily struggle to avoid predators and/or find food (which is part of why other animals are lagging behind in terms of mental capacity).

  • One can also say that particular tendencies in or capabilities of one's thinking (that are evolved and not learnt or anomalous) correspond to the physical structure of the brain, and changes there would be similar to changes in any other physical trait as far as evolution is concerned: tendencies show up as a result of mutations, and persist as a result of natural selection.

Non-reductionists would have a lot more difficulty in explaining exactly when consciousness first began, and accounting for any physical changes in the brain and changes in behaviour (not only via evolution across multiple organisms, but also for a single organism from brain injury, disease, drugs, brain chemicals or aging), and explaining how this connects back to consciousness.

  • Does the reductionist/functionalist view require that qualia can only emerge in carbon-based biological systems? Are carbon-based biological neurons strictly required? What about artificial intelligence, robots, or information processing systems built on transistors? Could you edit your answer to say something about that?
    – Mark
    Commented Nov 23, 2023 at 18:32
  • @Mark Edited...
    – NotThatGuy
    Commented Nov 23, 2023 at 20:06
  • Thanks. Now, a follow-up question.
    – Mark
    Commented Nov 23, 2023 at 20:25

Yes, qualia cause effects, but this does not by itself produce a survival advantage, because every organism has qualia. (Although the specific type of qualia a particular organism experiences may produce a survival advantage over other organisms.)

There's no gene to turn qualia on or off; qualia arise whenever information is used by the organism's brain to decide on behavior. Different causal structures will produce different qualia, but each causal structure produces - or corresponds to - some qualia.

To perceive a quale is to be influenced or disposed to react in a certain way. The quale can be said to be the disposition to react in a certain way specific to the quale; however that disposition arises, the same quale is there. "React," here, does not necessarily mean to take some outward muscular action. It could mean to take some information-processing action, for remembering the quale or combining it with other qualia.

Qualia are a perspective we may adopt about information processing in the organism's brain. "These neurons fired, causing the organism to turn left," is one perspective on an event. "The organism sensed a certain quale, so it turned left," is another, equivalent perspective; both perspectives describe the same ground truth.

  • Your answer seems to assume that carbon-based biological neurons are strictly required for qualia. Why? What about artificial neurons (as in artificial neural networks in the context of artificial intelligence) or information processing systems built on transistors? Can a robot experience a quale? Can a robot perceive the "redness of red"?
    – Mark
    Commented Nov 23, 2023 at 18:30
  • @Mark Yes, a robot can perceive the redness of red. I didn't say otherwise.
    – causative
    Commented Nov 23, 2023 at 18:37
  • Interesting, so you do believe that robots have consciousness. Do you think we have ethical obligations toward robots? Can robots experience pain and suffering?
    – Mark
    Commented Nov 23, 2023 at 18:38
  • 1
    @Mark Depends on the robot. I think a worm has consciousness and feels pain, but this does not mean we have much ethical obligation towards the worm (perhaps some). Moral standing depends on the specific type and complexity of consciousness. Particularly, if a consciousness is cognitively capable of engaging in social contracts, then that consciousness deserves some moral standing, at least to the extent it is willing to extend the same consideration to others.
    – causative
    Commented Nov 23, 2023 at 19:05

The ability to process sensory information is an evolutionary advantage. Same as an automatic vacuum cleaner with a camera will clean a room more efficiently than one equipped with just a bumper.

An early advantage is the ability to remember the connection of multiple sensory inputs, such as lightness and pain being remembered to avoid the light next time. The connection does not have to be learned, a lifeform can evolve to shun light without learning, but learning allows a lifeform to adapt to an environment that it was not born to fit in.

It stands to reason that the ability to process sensory data evolved along with the given senses, an animal without hearing would likely not prematurely develop the ability of processing sound by a mutation.

As such qualia are most likely just an efficient to produce way to process lots of information using neural networks. So the qualia themselves offer no benefit, the information processing from senses does.

So far it could not be proven that any qualia of humans can lead to special abilities in interacting with the environment that a computer with a similar sensor could not replicate in theory, even if contemporary systems may still be inferior in several ways.

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