Bernardo Kastrup

Yet, this paradigm is currently articulated in only a vague and promissory manner, in that neuroscience does not specify precisely or unambiguously what measurable parameters of neural processes map onto what qualities of subjective experience.
This is an important point, so let me belabor this a bit. If every conscious experience is nothing but a neural process, then there are two points-of-view from which to observe the same information flow associated with any experience: the perspective from the inside – that is, the experience itself – and the perspective from the outside – that is, what a neuroscientist sees when measuring the activity of a person’s brain while the person is having the experience. If materialism is correct, there always has to be a strict one-to-one correspondence between parameters measured from the outside and the qualities of what is experienced form the inside. After all, subjective experience supposedly is what is measured from the outside. For instance, if I see the color red, there have to be measurable parameters of the corresponding neural process in my brain that are always associated with the color red. After all, my experience of seeing red supposedly is the neural process.

As I mentioned above, neuroscience today is very far from being able to provide a consistent one-to-one mapping between the qualities of a subjective experience and measurable parameters of the corresponding neural process. It is possible to argue that this merely reflects our currently limited progress in finding this mapping and that it will be found in the future as more research is done and new techniques are developed for measuring the finer parameters of brain activity. As a vague and promissory argument, this is unfalsifiable. But we should keep two things in mind: first, decades of research and very high investments have already been made in the pursuit of this mapping, so it’s not like we’ve just started. Second, much of what we have found thus far seems to contradict the notion that there is any such consistent one-to-one mapping. Empirical observations reveal an inconsistent and even contradictory relationship between subjective experience and measurable parameters of neural processes. For instance, as neuroscientist Giulio Tononi mentions in the Elsevier Encyclopedia of Neuroscience, the firing of the same cortical neurons correlates with consciousness some times, but not other times.

Partly to deal with these contradictions, many neuroscientists speak of specificity: certain types of experience, regardless of their complexity or intensity, correlate with the activation of particular subsets of neurons, regardless of the amount of neurons or neural firings involved.37 Clearly, specificity breaks the one-to-one mapping between the qualities of subjective experience and the parameters of neural processes, for it does away with any kind of proportionality between the two. This is a delicate and often-contentious point, so let me expand on it a bit.
It is true that experience is not globally proportional to brain activation because, as we have seen, some neural processes are inhibitory, not excitatory. Depending on circumstances, the more certain inhibitory processes are active, the less basis there is for conscious experience. It is indeed known in neuroscience that consciousness is often correlated with interplay between excitatory and inhibitory processes. But that does not mean that one cannot expect local proportionality between an experience and the particular subset of neural activity that is the experience, whether there is inhibition going on around it or not. Obviously, the experience and that particular subset of neural activity should be proportional because, according to materialism, they are the same thing! And this is what specificity seems to throw out the window: if any subjective experience, regardless of complexity or intensity, can be any neural process, regardless of the number of neurons or firings involved, it becomes very difficult to see how the qualities of the experience can, in some way, be proportional to parameters of the neural process. And if it isn’t proportional, then clearly it cannot be the neural process

Either way, specificity does not spare materialists of the obligation to show a one-to-one, proportional mapping between the qualities of an experience and measurable parameters of the particular neural process that supposedly is the experience. That neuroscience seems unable to find this mapping shows that, unlike what is often claimed in the mainstream media, we are not making scientific progress in demonstrating that the brain generates the mind. As if to compound this state of contradiction, there isn’t even consensus that experience correlates with neural firings at all: some neuroscientists postulate, for instance, that mental states originate from unobservable quantum-level processes taking place within microtubules – microscopic structures in the neurons – regardless of whether neurotransmitters are being released or not

The problem here is this: to claim that a neural process suddenly becomes conscious when it integrates enough information is rather an appeal to magic than to cause-and-effect. What determines this magical threshold for Φ? Where is consciousness coming from? Why does sufficient information integration lead to the extraordinary and discontinuous phenomenon of otherwise unconscious neurons suddenly lighting up with consciousness? Now the neurons are unconscious; there comes a little more information; puff! Now they are conscious. Wait…What?

I hope to have established that the notion that consciousness is merely brain activity not only lacks explicit and specific elaboration, it cannot strictly be said to be supported by empirical observations.

Today, for instance, the fundamental subatomic particles described in the ‘Standard Model’ of particle physics are taken to be the irreducible building blocks of nature, on the basis of which everything else is supposedly explainable in principle.47 Materialism attempts to reduce conscious experience to physical entities like these particles. As such, it assumes consciousness to be derivative, not fundamental.

Today we find ourselves in a peculiar situation wherein, of all things, ignorance is often used to defend materialism: since nobody can specify unambiguously what physiological process supposedly is consciousness, neuroscientists can always postulate a different hypothetical mapping that conceivably explains any particular experience. All that is required is some –any – level of activity anywhere in the brain, which is not too difficult to find or reasonably assume. The problem, of course, is that one cannot postulate a different materialist theory of consciousness for each different situation and still claim that the evidence supports materialism.
The reason such surprising ambiguity is tolerated was already hinted at in : when it comes to consciousness, there is no way –not even in principle – to logically deduce the properties of subjective experience from the properties of matter.41 In other words, there is no way to logically deduce conscious perception, cognition, or feeling from the mass, momentum, spin, position, or charge of the subatomic particles making up the brain.

Tononi’s theory does not offer us any such causal chain in the case of consciousness. It does not allow us to deduce, not even in principle, the properties of the observed phenomenon – namely, subjective experience – from the properties of the processes correlated with it – namely, neural physiology. It only offers a heuristic indicator without any explanatory model. Nearly all relevant questions remain unanswered by Φ just like all relevant questions about how the car moves remain unanswered by the speedometer.
Since Tononi’s theory is claimed, by materialists, to be the best materialism has to offer, it is fair to conclude that, contrary to the impression often given by mainstream media, materialism currently does not offer an explanatory framework for tackling the mind-body problem. Does that mean that Tononi’s work is valueless? Most definitely not. Metaphysics aside, Φ has practical applications. For instance, it can potentially help us determine whether patients in seemingly vegetative states are actually conscious, as in total locked-in syndrome. There is tremendous human value in that. Moreover, the empirical observation that neural processes that correlate with conscious experience tend to be complex, closed cycles of information flow is also intriguing. However, as we shall see in , this observation in fact substantiates a non-materialist solution to the mind-body problem, not a materialist one.

So here we go: if consciousness is primary and irreducible, it cannot be the case that the brain generates it. How can we then explain the empirical observation that, ordinarily, mind states correlate well to brain states? The hypothesis I submit is that the function of the brain is to localize consciousness, pinning it to the space-time reference point implied by the physical body. In doing so, the brain modulates conscious perception in accordance with the perspective of the body. When not subject to this localization and modulation mechanism, mind is unbound: it entails consciousness of all there is across space, time, and perhaps beyond. Therefore, by localizing mind, the brain also ‘filters out’ of consciousness anything that is not correlated with the body’s perspective.