Consciousness, Illusionism, and the Existential Gap

By Nick Alonso

Philosophical discussions of consciousness took an interesting turn about a decade ago. Between the late 1970s and the early 2010s most philosophers discussed the seeming tension between science and consciousness, i.e., the objective, physics-based explanations that neuroscience provides us seems to fall short in explaining consciousness. Consciousness just seems to have a certain subjective character or what-it-is-likeness (e.g., the quality of what it is like to see red from the first person viewpoint) that does not seem amenable to objective, physics-based explanation. What this might imply about the nature of science and consciousness was the main focus of this discussion.

More recently, philosophers began to increasingly focus on a different question: is our sense that consciousness has some special subjective character accurate? Or might we be under some sort of cognitive illusion? The view that we are under some sort of illusion is called illusionism. Illusionism holds that the mysterious properties of consciousness that lie at the root of the hard problem do not exist, they only seem to exist, and therefore the hard problem of consciousness does not exist.

The nature of the disagreements between realists and illusionists are quite fascinating. For most realists, the issue with illusionism is not just that it is wrong, but that it is absurd. This absurdity almost always stems from a strong basic intuition that we have some certain knowledge about our own experience that is undeniable. How, after all, could we deny we have a stream of first-person experiences?!!

The aim of this post is for me to try to articulate the main reason I take illusionism seriously. I call this reason the existential gap. The basic idea is that from the third person point of view there is no good reason to believe that the mysterious properties at the root of the hard problem actually exist. Thus, from the third-person point of view, the one most scientists like myself privilege, there is no strong reason to believe in realism.

My ideas have been shaped by philosophers like Dan Dennett (e.g., here), Keith Frankish (e.g., here and here), Francois Kammerer (here), and scientists like Michael Graziano (here). However, I have yet to find particular paper that frames a motivation for illusionism in terms of a kind of existential gap. If any of you readers know of literature that has already framed components of the illusionist position in this or a similar way, please let me know in the comments!

Preliminaries

First, some definitions. By ‘consciousness’ I am referring to what philosophers call ‘phenomenal consciousness’, or subjective experience. I am not referring to self-consciousness, wakefulness, or other meanings of consciousness. Phenomenal consciousness (henceforth just consciousness or subjective experience) is at the root of the hard problem.

Examples of subjective experiences include visual, auditory, and tactile sensations, emotional feelings, and mental imagery. There is something it is like to have these mental states: there is something it is like to see red, to taste coffee, to feel pain, and to dream. What these experiences are like from the first person point of view, e.g., what red looks like or what pain feels like to the experiencer, is sometimes called phenomenality, subjective character, or what-it-is-likeness of the state. Let’s call the what-it-is-likeness/subjective character of a conscious state its WIL property.

The hard problem can be framed in these terms: e.g., how does certain neural activity give rise to mental states with WIL properties? The problem is that nothing about what we know about the brain seems to imply certain neural activity must yield a particular WIL property (e.g., an experience of red with a particular subjective character rather than no subjective character or a different kind).

Illusionists accept that the hard problem and WIL properties seem to exist, but deny that they actually do. From this claim, Illusionists have two options. First, they can argue that if WIL properties do not exist then consciousness does not exist, a view sometimes called eliminativism. Or they can argue that consciousness does exist, it just does not have any special WIL properties, a view we might call deflationism. My sense is that most illusionists take the deflationary route, saying consciousness does exist, it just does not have the mysterious properties is seems to. For more details on illusionism, I highly recommend the writings of Keith Frankish (e.g., here and here)

Science and The Existential Gap

The existential gap, which I develop below, is opposed to the widely discussed explanatory gap. The explanatory gap refers to the seeming gap between consciousness and objective, physical-functional descriptions of the brain. One way to frame this idea is that objective, physical-functional descriptions of the brain do not seem to entail facts WIL properties (e.g., physical-functional descriptions of the visual system do not seem to entail facts about what it is like to see the color red from the first-person point of view.)

The ontological gap refers to the potential metaphysical gap between brain and consciousness: if there is an ontological gap, the brain and consciousness are different kinds of things or have different kinds of properties: the brain has physical properties (location, mass, etc.), while consciousness has non-physical properties (e.g., subjective character/WIL properties).

Much of the philosophical debate over the last few decades has focused on the question whether the explanatory gap entails or suggests an ontological gap. Both the explanatory and ontological gap assume consciousness and its WIL properties exist.

Both the explanatory and ontological gap begin with the assumption WIL properties exist. Let’s, however, begin reasoning about consciousness under a more neutral assumption: WIL properties seem to exist to most people, but whether they actually do exist cannot be known prior to significant philosophical or scientific investigation. Let’s not just assume, in other words, prior to any philosophical or scientific investigation, that illusionists are wrong.

It is from this starting point that, I will now argue, that we find ourselves faced with a different kind of gap, what I call the existential gap. Its first approximation can be stated as follows:

• The Existential Gap: objective, physical-functional descriptions of the brain and behavior do not entail or provide strong reason to believe WIL properties exist.

Notice how this differs from the explanatory gap. The explanatory gap states that objective, physical-functional descriptions of the brain do not entail facts about WIL properties and therefore do not fully explain them. The existential gap, on the other hand, states that objective, physical-functional descriptions of the brain and behavior do not entail or even provide strong reason to believe WIL properties exist.

The explanatory gap is a claim about the limitations of our understanding of consciousness, under the assumption WIL properties exist. The existential gap is a claim about the limitations of the justification for our belief in WIL properties, while making no initial assumptions about whether WIL properties exist or not.

With these basic distinctions in place we can dive deeper into why and how the existential gap exists. Knowledge associated with consciousness that can be acquired from the third person point of view come from two sources of data: neural and behavioral data. I begin with a claim about neural data.

• Claim 1: there is no neural data that is difficult to explain in the deep philosophical sense that WIL properties seem to be. Nor is there anything observable in the brain that entails or provides strong reason to believe such properties exist.

When we look at a living, awake, conscious person’s brain with our own eyes or through some brain scanning or measuring device, we do not observe anything like WIL properties. Nor do we seem to observe anything that is hard to explain in the way WIL properties are supposed to be. I do not know of any philosopher or scientist who would deny this claim. Further, while the brain is complicated, there is no deep philosophical problem preventing our understanding (in principle) of its observable physical-computational processes like there is for WIL properties.

However, even if WIL properties are not directly observable in the brain from the third-person point of view, it could still be that they are implied/strongly suggested to exist by something that is directly observable in the brain. The Higgs Boson particle, for instance, was implied to exist by certain mathematical theories/models in physics before its actual measurement. Maybe WIL properties are similar. However, nothing we know of yet about the brain, and no well-justified theories that seek to explain neural data, imply the existence of WIL properties or strongly suggests they exist. Those who disagree have the burden of finding a theory or model from neural science, that does not assume the existence of WIL properties a priori, which does indeed entail there existence. As someone who has worked on formal theories from neuroscience, like predictive coding, I do not know if any such theory.

It is important to emphasize: if we assume WIL properties exist and that WIL properties are identical to some observable stuff in the brain, then that observable stuff in the brain implies the existence of WIL properties. However, such theories would not be consistent with our neutral assumption about the existence of WIL properties. Formal cognitive and neural models of the brain that were built to fit neural data simply do not imply the existence of anything like WIL properties.

These same points apply to behavioral data.

• Claim 2: There is no behavioral data that entails or strongly suggests the existence of WIL properties. This behavioral data includes people’s strong tendency to claim WIL properties exist, and any other associated behavior.

Consider an intuitive argument: the fact that people tend to claim they have conscious states with WIL properties needs an explanation, i.e., it needs a description of what causes that behavior. The most plausible explanation is that WIL properties cause people to claim they have WIL properties…duh.

Although this argument is intuitive, it is wrong. Any human behavior has a (causal) explanation that is entirely consciousness-neutral, i.e. an explanation that only involves concecpts of neural or cognitive-computational mechanisms. There has never been a behavior observed that could not be accounted for sufficiently by the physical-computational happenings in the brain and peripheral nervous system. The physical-computational happenings in the brain do not provide reason to believe in WIL properties (see above), and their causal effects on behavior should not either. Your claim that you are conscious can be sufficiently explained in terms of your neural mechanisms and cognitive level computations. There is no reason to think there is anything extra going on just because we tend to say WIL properties exist.

This may sound unusual to some. After all, what sorts of cognitive/neural processes would cause us to say WIL properties exist, even if WIL properties do not exist? Why would our cognitive systems do this? This question has now been discussed at length by philosophers and some cognitive scientists. For a review of various ideas, see David Chalmers paper on the Meta-Problem. The general idea is that certain cognitive systems in your brain make judgments about your own mental states. Due to certain quirks about the way your brain represents information about itself and the physical world, and quirks in the functioning of your cognition, your cognitive systems make certain faulty conclusions about the nature of your own mental states, not unlike the way your visual or auditory systems have quirks that lead them to create certain faulty perceptual representation (e.g., optical illusions). In the end, the fact that people tend to say they have mental states with WIL properties only entails that there is some cognitive-computational process, implemented in neural mechanisms, causing this behavior. It does not alone entail WIL properties exist, nor does this behavior alone provide a clear strong reason to believe there is something beyond the cognitive and neural processes that cause the behavior.

So neural data and behavioral data do not provide strong reason to believe in the existence of WIL properties. Then why do most scientists and philosophers interested in consciousness seem to believe in WIL properties? I cannot speak for everyone, but every argument I have personally heard from scientists and philosophers, and the assumptions they seem to implicitly make, always reverts back to first-person experience, e.g., they will say something along the lines of “If I know anything it is that I have conscious states with subjective character! It is undeniable knowledge that it is like something for me to see red, taste coffee, etc.!”

• Claim 3: there has yet to be a plausible explanation of how a brain gains infallible knowledge of something like WIL properties.

Remember, we started with a neutral assumption about whether WIL properties exist. Simply asserting that one knows they exist prior to empirical or rigorous philosophical investigation violates this assumption. However, we can still ask the question of whether some cognitive system in the brain exists that makes (nearly) infallible judgments about our own mental states. We can investigate such a system empirically, and if such a system seems to exists, and it concludes WIL properties exist, this might provide some reason to believe in WIL properties.

But, how would such an infallible system even work? Appeals to an “I” that “knows” with certainty about its own WIL properties is not helpful. After all, what the heck is an “I” and how does this perfectly reliable knowledge relation between the ‘I’ and WIL properties even work? These are question illusionists like Dennett have been asking for decades (see also here by Frankish).

More plausibly, there is no special ‘I’ in the brain with special, infallible knowledge, a point Dan Dennett (e.g., here) has be making for decades. Most cognitive scientists hold there is some sort of dedicated meta-cognitive system in the brain tasked with identifying and reasoning about our own and others’ mental states. The most plausible view of such a system is that it is fallible. Sure, maybe our meta-cognitive system has some privileged access to our own mental states that outside observers do not, but they will not have infallible access. All cognitive systems are imperfect, due to time, computation, and memory constraints, etc.

Further, we know certain systems in the brain, although highly useful, systematically misrepresent things. The human perceptual system systematically falls prey to certain illusions: present the human visual system with a certain kind of visual stimuli, and the subject will claim something is in the environment that is not. It is therefore perfectly possible that the same is true of meta-cognition: present our meta-cognitive system with a certain kind of input, and the subject will claim something is in their mind that is not.

If we can be deceived about the external world because of quirks in our perceptual systems, we can also deceived about our own internal mental world because of quirks in our meta-cognitive system. Appeals to first person experience are not an argument/or reason against this point, simply an assertion of the conclusion one is trying to support. Again, we are left with no convincing reason to believe WIL properties exist.

Conclusions

The existential gap implies something important: for the many scientists like myself who believe our best bet at understanding nature is to take up the third-person point of view and apply the scientific method, Illusionism is not only far from absurd but it seems inescapable. Nothing we can understand about nature from the third-person point of view implies or even strongly suggests WIL properties actually exist.

Those who vehemently oppose illusionism tend to do so on the basis of their first person experience, claiming that from the first-person point of view, they/the mysterious ‘I’ have certain knowledge of the existence of WIL properties: WIL properties are data that needs to be explained by science, period. The problem is these claims are made without providing any scientifically plausible account of what this ‘I’ even is or how it could come to have certain knowledge of WIL properties. Without such an account, it seems a better starting point is to investigate scientifically whether WIL properties actually exist. However, once we do this, the existential gap presents itself, and we seem unable to find our way back to any great justification to believe in WIL properties or the hard problem.