Friston vs Brogaard: Down the Rabbit Hole - part 2

HEAD TO HEAD: If we cannot trust our senses, where does this leave our beliefs?

Read part 1: Karl Friston asks, is our experience real, or simply a construct of the brain?

Experience is a construct of the brain. I think all the discussants in the Down the Rabbit Hole debate agreed with this position. I would like to add to this that we furthermore have no control over how our brain constructs our experiences. Experiences are not the result of rationally controlled conscious processes. It takes place at a level Daniel Dennett once referred to as “the sub-personal level”.

According to Dennett in Content and Consciousness, the distinction between personal level and sub-personal level explanations is the distinction between “the explanatory level of people and their sensations and activities and the sub-personal level of brains and events in the nervous system”. Personal level explanations are distinctive kinds of explanation for persons. Dennett continues:

When we've said that a person is in pain, that she knows which bit of her hurts and that this is what's made her react in a certain way, we've said all that there is to say within the scope of the personal vocabulary.... If we look for alternative modes of explanation, we must abandon the explanatory level of people and their sensations and activities and turn to the sub-personal level of brains and events in the nervous system.

So although personal-level explanations may refer to a-rational mental states, like pain, they can also refer to mental states that are assessable for rationality, such as “needs, desires, intentions and beliefs”. Subpersonal-level explanations, on the other hand, are not concerned with normative properties such as that of being rational; they merely make reference to causal relations and mechanisms.


"There is no way to tell whether an experience radically misrepresents. Nor can science provide us with an answer."

As our experiences are produced by our brains at a sub-personal level, we do not have any conscious access to the processes that go into constructing them. What we have conscious access to is just the experience. There is therefore no way to tell whether an experience radically misrepresents from an internal point of view. Nor will it help to ask other people about my experiences. Nor will science be able to provide us with an answer. If I am a brain in a vat or a citizen of The Matrix, I may be given a huge amount of enormously convincing evidence that the world is as I see it, even though it is not.

Karl Friston argues that “the problem with this sceptical take on ‘experience as inference’ is that it presupposes the existence of a sensorium. In other words, if I am making inferences, there must be something out there to infer.”

If we take what Friston here says at face value, then I must disagree. As Friston duly notes, we have hallucinations, dreams etc. “when deprived of sensory evidence". In other words, we sometimes have experiences even when there is no “sensorium” in Friston’s sense. But if we cannot tell whether our experiences radically misrepresent, then that leaves open the very real possibility that we are always or nearly always constructing our experiences in the absence of a “sensorium”.

There is, of course, a sense in which Friston is right. Even if we are brains in a vat, there must be “something” out there (even the radical idealist Bishop Berkeley thought that there was “something” out there). My point here is merely that the phenomenology of our experiences need not have any similarities to the character of what is out there.

Does this position commit us to some kind of radical scepticism? Well, it depends on what we take justification to consist in. If we take our experiences to provide justification for our beliefs, we can say that our experience-based beliefs, for the most part, are justified. However, even if we hold the view that our beliefs, for the most part, are justified, we cannot infer from this that we somehow have direct conscious access to an external reality. There is no way that we could have any such direct conscious access, and there is therefore always a real chance that all of our experiences are misrepresenting whatever is out there.

Read part 1: Karl Friston asks, is our experience real, or simply a construct of the brain

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