François Kammerer’s research while affiliated with French National Centre for Scientific Research and other places

Ulysses, the strong illusionist, sails towards the Strait of Definitions. On his left, Charybdis defines “phenomenal consciousness” in a loaded manner, which makes it a problematic entity from a physicalist and naturalistic point of view. This renders illusionism attractive, but at the cost of committing a potential strawman against its opponents – phenomenal realists. On the right, Scylla defines “phenomenal consciousness” innocently. This seems to render illusionism unattractive. Against this, I show that Ulysses can pass the Strait of Definitions. He should sail straight towards Scylla. Supposedly innocent definitions land a concept that makes illusionism attractive without committing a strawman. Indeed, this concept, which captures what the phenomenal realist means, is explicitly innocent but implicitly loaded. Beyond the Strait lies another danger: the Sirens of Redefinitions. They incite our hero to redefine his terms to salvage verbally (weak) phenomenal realism – judged preferable to overt strong illusionism. Ulysses should resist the Sirens’ songs and choose overt strong illusionism over its weak realist reformulation.

This paper reflects on and replies to the fifteen contributions responding to our target article 'What Forms Could Introspective Systems Take? A Research Programme' (all found in this issue). We focus first on contributions that criticize our research programme, then turn to ones that test our framework against various views and models of human introspection, and finally consider contributions that explore possible variations of introspection in humans, non-human animals, current AI systems, and imaginary minds. We conclude by drawing some lessons for our research programme and making some suggestions for future research on possible forms of introspection.

We propose a new approach to the study of introspection. Instead of asking what form introspection actually takes in humans or other animals, we ask what forms it could take, in natural or artificial minds. What are the dimensions along which forms of introspection could vary? This is a relatively unexplored question, but it is one that has the potential to open new avenues of study and reveal new connections between existing ones. It may, for example, focus attention on possible forms of introspection radically different from the human one and help to integrate competing theories of human introspection in a non-adversarial manner. We introduce and motivate the project, provide a preliminary mapping of the space of possible forms of introspection, and sketch a programme for interdisciplinary research on the topic.

Illusionism is the thesis that phenomenal consciousness does not exist, but merely seems to exist. Many opponents to the thesis take it to be obviously false. They think that they can reject illusionism, even if they conceded that it is coherent and supported by strong arguments. David Chalmers has articulated this reaction to illusionism in terms of a “Moorean” argument against illusionism. This argument contends that illusionism is false, because it is obviously true that we have phenomenal experiences. I argue that this argument fails (or is dialectically irrelevant) by showing that its defenders cannot maintain that its crucial premise (properly understood) has the kind of support needed for the argument to work, without begging the question against illusionism.

Illusionists claim that phenomenal consciousness does not exist, but merely seems to exist. Most debates concerning illusionism focus on whether or not it is true—whether phenomenal consciousness really is an illusion. Here I want to tackle a different question: assuming illusionism is true, what kind of illusion is the illusion of phenomenality? Is it a “rich” illusion—the cognitively impenetrable activation of an incorrect representation—or a “sparse” illusion—the cognitively impenetrable activation of an incomplete representation, which leads to drawing incorrect judgments? I present this distinction and I classify the most influential illusionist theories along this line of divide. I then offer an argument against the accounts of the illusion of phenomenality in terms of sparse illusion.

Phenomenal consciousness appears to be particularly normatively significant. For this reason, sentience-based conceptions of ethics are widespread. In the field of animal ethics, knowing which animals are sentient appears to be essential to decide the moral status of these animals. I argue that, given that materialism is true of the mind, phenomenal consciousness is probably not particularly normatively significant. We should face up to this probable insignificance of phenomenal consciousness and move towards an ethics without sentience.

Why do we tend to think that phenomenal consciousness poses a hard problem? The answer seems to lie in part in the fact that we have the impression that phenomenal experiences are presented to us in a particularly immediate and revelatory way: we have a sense of acquaintance with our experiences. Recent views have offered resources to explain such persisting impression, by hypothesizing that the very design of our cognitive systems inevitably leads us to hold beliefs about our own experiences with certainty. I argue against this kind of “designed certainty” views. First, I claim that it is doubtful that we really hold beliefs about our own experiences with certainty—in any sense of certainty that would make our phenomenal beliefs special. Second, I claim that, even if it were the case that we hold beliefs about experiences with certainty, this would fall short of explaining our sense of acquaintance.

Illusionism about phenomenal consciousness is the thesis that phenomenal consciousness does not exist, even though it seems to exist. This thesis is widely judged to be uniquely counterintuitive: the idea that consciousness is an illusion strikes most people as absurd, and seems almost impossible to contemplate in earnest. Defenders of illusionism should be able to explain the apparent absurdity of their own thesis, within their own framework. However, this is no trivial task: arguably, none of the illusionist theories currently on the market is able to do this. I present a new theory of phenomenal introspection and argue that it might deal with the task at hand.