The overwhelmingly validated theory of evolution tells us that the functions performed by our organs arose from associated increases in survival fitness. For instance, the bile produced by our liver and the insulin produced by our pancreas help us absorb nutrients and thus survive. Insofar as it is produced by the brain, our phenomenal consciousness—i.e. our ability to subjectively experience the world and ourselves—is no exception: it, too, must give us some survival advantage, otherwise natural selection wouldn’t have fixed it in our genome. In other words, our sentience—to the extent that it is produced by the brain—must perform a beneficial function, otherwise we would be unconscious zombies.

One problem with this is that, under the premises of materialism, phenomenal consciousness cannot—by definition—have a function. According to materialism, all entities are defined and exhaustively characterised in purely quantitative terms. For instance, elementary subatomic particles are exhaustively characterised in terms of e.g. mass, charge and spin values. Similarly, the behaviour of abstract fields is fully defined in terms of quantities, such as frequencies and amplitudes of oscillation. Particles and fields, in and of themselves, have quantitative properties but no intrinsic qualities, such as colour or flavour. Only our perceptions of them—or so the materialist argument goes—are accompanied by qualities somehow generated by our brain.

Materialism posits that the quantities that characterise physical entities are what allow them to be causally efficacious; that is, to produce effects. For instance, it is the charge values of protons and electrons that produce the effect of their mutual attraction. In nuclear fission reactors, it is the mass value of neutrons that produces the effect of splitting atoms. And so on. All chains of cause and effect in nature must be describable purely in terms of quantities. Whatever isn’t a quantity cannot be part of our physical models and therefore—insofar as such models are presumed to be causally-closed—cannot produce effects. According to materialism, all functions rest on quantities.

Our phenomenal consciousness is eminently qualitative, not quantitative. There is something it feels like to see the colour red, which is not captured by merely noting the frequency of red light.

However, our phenomenal consciousness is eminently qualitative, not quantitative. There is something it feels like to see the colour red, which is not captured by merely noting the frequency of red light. If we were to tell Helen Keller that red is an oscillation of approximately 4.3*1014 cycles per second, she would still not know what it feels like to see red. Analogously, what it feels like to listen to a Vivaldi sonata cannot be conveyed to a person born deaf, even if we show to the person the sonata’s complete power spectrum. Experiences are felt qualities—which philosophers and neuroscientists call ‘qualia’—not fully describable by abstract quantities.

But as discussed above, qualities have no function under materialism, for quantitatively-defined physical models are supposed to be causally-closed; that is, sufficient to explain every natural phenomenon. As such, it must make no difference to the survival fitness of an organism whether the data processing taking place in its brain is accompanied by experience or not: whatever the case, the processing will produce the same effects; the organism will behave in exactly the same way and stand exactly the same chance to survive and reproduce. Qualia are, at best, superfluous extras.

Therefore, under materialist premises, phenomenal consciousness cannot have been favoured by natural selection. Indeed, it shouldn’t exist at all; we should all be unconscious zombies, going about our business in exactly the same way we actually do, but without an accompanying inner life. If evolution is true—which we have every reason to believe is the case—our very sentience contradicts materialism.

This conclusion is often overlooked by materialists, who regularly try to attribute functions to phenomenal consciousness. Here are three illustrative examples:

(1) consciousness enables attention.

(2) consciousness discriminates episodic memory (past) from live perceptions (present) by making them feel different.

(3) consciousness motivates behaviour conducive to survival.

Computer scientists know that none of this requires experience, for we routinely implement all three functions in presumably unconscious silicon computers.

Regarding point 1, under materialism attention is simply a mechanism for focusing an organism’s limited cognitive resources on priority tasks. Computer operating systems do this all the time—using techniques such as interrupts, queuing, task scheduling, etc.—in a purely algorithmic, quantitatively-defined manner.

Regarding point 2, there are countless ways to discriminate data streams without need for accompanying experience. Does your home computer have trouble separating the photos of last year’s holidays from the live feed of your webcam? Data streams from memory and real-time processes can simply be tagged or routed in different ways, without qualia.

Finally regarding point 3, within the logic of materialism motivation is simply a calculation - the output of a quantitative algorithm tasked with maximising the gain while minimising the risk of an organism’s actions. Computers are ‘motivated’ to do whatever it is they do—otherwise they wouldn’t do it—without accompanying qualia.

The impossibility of attributing functional, causative efficacy to qualia constitutes a fundamental internal contradiction in the mainstream materialist worldview.

Just as these three examples illustrate, all conceivable cognitive functions can, under materialist premises, be performed without accompanying experience. Nonetheless, we regularly see scientific publications proposing a function for consciousness. A recent Oxford University Press blog post, for instance, claims that ‘the function of consciousness is to generate possibly counterfactual representations of an event or a situation’, which ‘hint at the origins of consciousness in the course of evolution’.

If one reads it attentively, however, one realises that the article defines what is meant by ‘function of consciousness’ in a rather counterintuitive manner that contradicts the way any casual reader would interpret the words:

‘When we consider functions of consciousness, they are the functions that are enabled by stimuli that enter consciousness or the functions that can be performed only in awake humans or animals. Functions in this sense should not be confused with the question of what kind of effects conscious experiences (or qualia) exert on physical systems.’

In other words, what the author calls the ‘functions of consciousness’ aren’t the cognitive tasks performed by consciousness, but simply those visible to consciousness—i.e. reportable through conscious introspection. Why call these tasks the ‘functions of consciousness’ if they aren’t what consciousness does, but merely what it sees? According to this argument, phenomenal consciousness expressly isn’t the causative agency behind these tasks—for the article excludes the causal efficacy of qualia from the definition—but merely their audience. As such, this theory is somewhat beside the point, as far as the survival value of having qualia or the evolutionary origins of phenomenal consciousness proper.

The impossibility of attributing functional, causative efficacy to qualia constitutes a fundamental internal contradiction in the mainstream materialist worldview. There are two main reasons why this contradiction has been accepted thus far: first, there seems to be a surprising lack of understanding, even amongst materialists, of what materialism actually entails and implies. Second, deceptive word games—such as that discussed above—seem to perpetuate the illusion that we have plausible hypotheses for the ostensive survival function of consciousness.

Phenomenal consciousness cannot have evolved. It can only have been there from the beginning as an intrinsic, irreducible fact of nature. The faster we come to terms with this fact, the faster our understanding of consciousness will progress.

If you want to hear from leading thinkers like this debating renowned philosophers, cutting edge scientists, headline-making politicians, and beloved artists, come to HowTheLightGetsIn Hay 2020 for four days of debates and talks alongside music, comedy and parties.

Bernardo Kastrup will be appearing in The Limits of Material discussing consciousness and idealism.