Sensation and perception is a limited view and also the only point of access to reality we have. This said, then, we should think it is important. No sensation and perception necessarily means no understanding of and no interaction with reality.
This is, of course, if there is another reality that is unknown. But why complicate things when one reality is already complicated enough. Reality has no cause for being more complex than need be.
The onus is on others to explain why the metaphysical is needed.
I am happy with a mechanistic explanation of us. That the illusion of a self or rationality should be no less plausible than phenomena or representation. To react against the physical reality is really an unnecessary fear that brings about more grief than relief.
As a Buddhist correct understand brings about relief. The explanation is not that different to a philosophically material monist one. The self is not what it seems. A soul is as plausible as a non-soul. To discount non-self is not scientific, not open-minded. It is foreign. It is The Other.
The Experience is the source of all knowledge. By experience I mean sensation from the senses. The five basic senses are the eyes, ears, skin, nose, and tongue, in the modes of sight, sound, touch, smell, and taste respectively. Perception is also part of experience. Perception is the interpretation of the physical data from the senses and also the interpretation of the concepts (mental data). Conceptualisation is a part of this experience. It is the accumulation of concepts – physical and mental data – that I term knowledge. Signification (language) is the part of this experience of this particular animal.
Without sensory experience we do not have knowledge. The beginning of sensory experience is what we call life, and its end is death. Everything in between is The Experience.
The dispute between rationalism and empiricism concerns the extent to which we are dependent upon sense experience in our effort to gain knowledge. Rationalists claim that there are significant ways in which our concepts and knowledge are gained independently of sense experience. Empiricists claim that sense experience is the ultimate source of all our concepts and knowledge.
From Stanford Encyclopaedia of Philosophy.
I agree with Rationalists that concepts and knowledge can be gained independently of sense experience, insofar as there is nothing outside of space-object-time. Some kind of knowledge must exist first of space-object-time before other kinds of concepts and knowledge can come into being independently.
Empiricist are therefore right to claim also that sense experience is the source of all our concepts and knowledge, insofar as rational concepts and knowledge depends on the first source of sense experience.
There are therefore two sources of knowledge – sense experience and reasoning. Rationality must come from the first instance of sense experience, be it a lifetime of one second or one hundred years. Without that “spark” there are no rational concepts and knowledge.