Why the Epistemology of Conscious Perception Needs a Theory of Consciousness

On a certain type of classical "foundationalist" view in epistemology, knowledge of your sensory experience grounds knowledge of the outside world: Your knowledge that you're seeing a tree, for example, is based on or derived from your knowledge that you're having sensory experiences of greens and browns in a certain configuration in a certain part of your visual field. In earlier work, I've argued that this can't be right because our knowledge of external things (like trees) is much more certain and secure than our knowledge of our sensory experiences.

Today I want to suggest that foundationalist or anti-foundationalist claims are difficult to evaluate without at least an implicit background theory of consciousness. Consider for example these three simple models of the relation between sensory experience, knowledge of sensory experience, and knowledge of external objects. The arrows below are intended to be simultaneously causal and epistemic, with the items on the left both causing and epistemically grounding the items on the right. (I've added small arrows to reflect that there are always also other causal processes that contribute to each phase.)

[apologies for blurry type: click to enlarge and clarify]

Model A is a type of classical foundationalist picture. In Model B, knowledge of external objects arises early in cognitive processing and informs our sensory experiences. In Model C, sensory experience and knowledge of external objects arise in parallel.

Of course these models are far too simple! Possibly, the process looks more like this:

How do we know which of the three models is closest to correct? This is, I think, very difficult to assess without a general theory of consciousness. We know that there's sensory experience, and we know that there's knowledge of sensory experience, and we know that there's knowledge of external objects, and that all of these things happen at around the same time in our minds; but what exactly is the causal relation among them? Which happens first, which second, which third, and to what extent do they rely on each other? These fine-grained questions about temporal ordering and causal influence are, I think, difficult to discern from introspection and thought experiments.

Even if we allow that knowledge of external things informs our sense experience of those things, that can easily be incorporated in a version of the classical foundationalist model A, by allowing that the process is iterative: At time 1, input causes experience which causes knowledge of experience which causes knowledge of external things; then again at time 2; then again at time 3.... The outputs of earlier iterations could then be among the small-arrow inputs of later iterations, explaining whatever influence knowledge of outward things has on sensory experiences within a foundationalist picture.

On some theories, consciousness arises relatively early in sensory processing -- for example, in theories where sensory experiences are conscious by virtue of their information's being available for processing by downstream cognitive systems (even if that availability isn't much taken advantage of). On other theories, sensory consciousness arises much later in cognition, only after substantial downstream processing (as in some versions of Global Workspace theory and Higher-Order theories). Although the relationship needn't be strict, it's easy to see how views according to which consciousness arises relatively early fit more naturally with foundationalist models than views according to which consciousness arises much later.

The following magnificent work of art depicts me viewing a tree:

[as always, click to enlarge and clarify]

Light from the sun reflects off the tree, into my eye, back to primary visual cortex, then forward into associative cortex where it mixes with associative processes and other sensory processes. In my thought bubble you see my conscious experience of the tree. The question is, where in this process does this experience arise?

Here are three possibilities:

Until we know which of these approaches is closest to the truth, it's hard to see how we could be in a good position to settle questions about foundationalism or anti-foundationalism in the epistemology of conscious perception.

(Yes, I know I've ignored embodied cognition in this post. Of course, throwing that into the mix makes matters even more complicated!)

Post a Comment