I just started reading Shaun Gallagher and Dan Zahavi’s textbook The Phenomenological Mind and I thought this was a particularly clear paragraph on the relevance on phenomenology to cognitive science.
Compare two situations. In the first situation we, as scientists who are interested in explaining perception, have no phenomenological description of perceptual experience. How would we begin to develop our explanation? We would have to start somewhere. Perhaps we would startwith a pre-established theory of perception, and begin by testing the various predictions this theory makes. Quite frequently this is the way that science is done. We may ask where this pre-established theory comes from, and find that in part it may be based on certain observations or assumptions about perception. We may question these observations or assumptions, and based on how we think perception actually works, formulate counter-arguments or alternative hypotheses to be tested out. This seems somewhat hit or miss, although science often makesprogress in this way. In the second situation, we have a well-developed phenomenological description of perceptual experience as intentional, spatial, temporal, and phenomenal. We suggest that starting with this description, we already have a good idea of what we need to explain. If we know that perception is always perspectivally incomplete, and yet that we perceive objects as if they have volume, and other sides that we cannot see in the perceptual moment,then we know what we have to explain, and we may have good clues about how to design experiments to get to just this feature of perception. If the phenomenological description is systematic and detailed, then to start with this rich description seems a lot less hit or miss. So phenomenology and science may be aiming for different kinds of accounts, but it seems clear that phenomenology can be relevant and useful for scientific work.
~The Phenomenological Mind, Shaun Gallagher and Dan Zahavi, p. 9-10
This general idea is echoed in Julian Jaynes’ quip that the attempt to find consciousness in the brain will inevitably fail unless you know what you are looking for in the first place.