This is a pathbreaking conversation with Dr. Johannes Kleiner, a mathematician and physicist at the Munich Center for Mathematical Philosophy. He works at the cutting edge of an ever urgent question — is the universe conscious? He explains to Grin why the answer could well be, yes.
1. What do you mean when you say that ‘the universe might be conscious’ or the ‘universe might experience consciousness’?
In order to explain this, I need to take a bit of a swing. My research is concerned with what is called “models of consciousness”. A model of consciousness is a scientific theory that attempts to explain how conscious experience and the physical domain (brain states, etc.) are connected.
In the previous thirty years, many ideas have been put forward for how models of consciousness could be constructed. Some are based on empirical results from neuroscience or psychology, others are based on purely theoretical ideas. The vast majority of these models is not mathematical in nature, but rather formulated in terms of ordinary (scientific) language. However, in the recent decade, some models have been proposed that are more formal in nature, among them a model called ‘Integrated Information Theory’, which is very successful.
This has brought me and a few colleagues to study mathematical models of consciousness. We’re investigating, e.g., what advantage mathematical tools have in the scientific study of consciousness compared to non-mathematical methodologies, and which implications characteristic features of consciousness, such as its private and subjective nature, have for scientific models of consciousness.
The crucial ingredient in constructing and studying mathematical models of consciousness is to represent conscious experience in mathematical terms. This is what makes mathematical models of consciousness so powerful. One can use what is called a ‘mathematical space’ to represents the content of conscious experience. Once provided with some mathematical description of the physical domain (e.g. of the neural network in the brain), on can then apply a model of consciousness to calculate which conscious experience it would have.
Now the crucial ingredient here is that any physical system that can be represented mathematically (in principle) can be ‘plugged into’ a model of consciousness to calculate the conscious experience of that system according to that model. Next to brains, this could be a mathematical description of a computer, a large network or even a approximate mathematical description of the universe.
This is where the headline you have quoted above comes from. Mathematical models of consciousness allow us to calculate the conscious experience of all sorts of systems. And while a final verdict is still pending of which model of consciousness describes reality correctly, it is a possibility that the universe as a whole has some conscious experience.
2. Could you explain the Integrated Information Theory in a manner that most people would understand?
Let me try. Integrated Information Theory is a mathematical model of consciousness. So as explained above, it takes as input some mathematical description of a physical system and gives as output both the content and intensity of the system’s conscious experience, described in mathematical terms. In mathematical termniology, this is called a ‘mapping’ from physical systems, one the one hand, to spaces of conscious experience, on the other.
The crucial ingredient in Integrated Information Theory is to define this mapping in a particular way. Think about your computer. It receives signals from the telephone cable and converts them into text you can read in you web browser. This process is nowadays described in terms of information: The computer receives information from the telephone cable, transforms this information suitably, and then displays this information to you in the web browser.
Crucially, there are various different ways in which information can be transformed. Whereas for some websites, the transformation would be relatively ‘straightforward’, for other websites (e.g. ones that contain a complicated browser game) the transformation would be more involved, requiring the computer to pass information from some parts of its processors back to other parts several times. This is called ‘recurrent’ processing, and a computer or brain that carries out a lot of recurrent processing is called ‘integrated’.
This is enough to explain the key intuition behind Integrated Information Theory. This theory is built up in such a way that systems which are doing a lot of recurrent processing — i.e. whose information processing is strongly integrated — exhibit a larger degree of consciousness than systems who are not doing any significant recurrent processing.
To spell this out in detail, and to explain how the theory defines the content of consciousness in terms of integrated information requires a lot of mathematical tools. But the above is the fundamental intuition: The more integrated a system’s information processing is, the more consciousness it has.
3. If we comprehensively conclude that the universe (and indeed inanimate things) can experience consciousness — how does this dramatically change our perception of the universe and indeed our own selves?
Most scientist (including me, sometimes) think that all that exists are physical things — atoms, molecules and the like — and that these physical things make up the whole universe and everything that we can see and interact with. What we call consciousness is completely determined by these physical things. Consciousness does not make a difference to how the universe ‘ticks’.
This view is called epiphenomenalism. Physicalism, the idea that consciousness is nothing but a particular property some physical systems can have, e.g. that of representing an ‘outside world’ in a particularly efficient manner, is a special case thereof.
If there were any conclusive evidence that consciousness played a genuine causal role in the universe, that it is something that ‘is in the world’ next to physical quantities, that would have enormous consequences for the scientific view of the world. Evidence of this sort might lead to a scientific revolution no less extreme than the ones initiated by Nikolaus Kopernikus or Galileo Galilei.
4. Where does this understanding of ‘the universe might be conscious’ fit into the debate between string theory and loop quantum gravity theory?
Both string theory and loop quantum gravity compete to give a unified description of the physical reality. — A description from which everything else that physics describes follows. If epiphenomenalism were wrong, so that conscious experience itself could induce a change to how physical systems evolve, neither of the two theories could claim to be a full description of reality. They would have to be classified as omitting an important part of reality — conscious experience.
5. For a long time, we discussed the ‘hard problem of consciousness’, does that IIT help us transcend this? And if yes, how?
There are many different conceptions of what people mean when the use the term ‘hard problem’. For example, a prevalent definition among philosophers asserts that there is a metaphysical possibility that conscious experience would “attach” to the physical world in a completely different manner than it actually does. Thus, so the argument goes, there need to be laws of nature which specify how consciousness actually attaches to the physical domain. These laws are referred to as ‘nomological necessity’.
This characterization of the hard problem is somewhat problematic as one can ask just what justifies the initial claim of metaphysical possibility. But in case that’s what you have in mind, IIT would certainly address it. IIT is a proposal for a law of nature that would do the job required by this understanding of the hard problem.
Some think of the hard problem more in terms of intelligibility. The task, according to this conception, is that we need to make it intelligible why consciousness exists and why it attaches to the physical domain just in the way it does. Here, I am a bit less optimistic concerning IIT. For even if it were fully correct, I can’t see how it would answer the ‘why’ question. It would just be a fact about nature which we have to take into account, and might not satisfy our itch of curiosity completely.
My most favourite conception of the hard problem is in terms of what is often called an ‘explanatory gap’. Here, the idea is that conscious experience might be a phenomenon that has certain properties that render it incompatible with each and every one of the types of explanation used in natural science. If that were the case, we wouldn’t even know how to start explaining conscious experience scientifically. There would be a gap between conscious experience and natural science when it comes to scientific explanation, hence ‘explanatory gap’.
This doesn’t mean that we can’t ever explain conscious experience. But it requires us to make changes to what we call a scientific explanation, and might require us to develop completely new forms of explanation.
If there were an explanatory gap, IIT in its current form would not be solving the hard problem. It is a scientific theory similar to many other theories in other fields and does make use of the usual way of explaining things in more mathematical sciences. But its mathematical structure could possibly be adapted to more advanced modes of explanation. So there certainly is hope!
6. In a post-pandemic world, would it be correct to say that a deeper understanding of consciousness is not only important, but urgent? If yes, why?
Within science, I think there is no other problem which is as deep, as puzzling and as mysterious as the problem of consciousness, and I think much can be gained if we make progress in uncovering this mystery. My hope is that eventually, this might help us to create a better world, e.g. by supporting the development of new cures for medical diseases associated with conscious perception. The road may be long, but I think it’s worth taking it.
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