   Now that we know how and why Reid argues against the Way of Ideas' representational theory of perception, we needn't address these questions in order to continue with a discussion of the components of Reid's own more direct theory of perception. Here we need to keep in mind the fact that, though contemporary philosophers write a priori about perception, sensation, and knowledge, Reid does not offer necessary and sufficient conditions for perception or for its component processes. Consistent with his Newtonian empiricism, Reid is aiming for something else altogether: observations and accurate experiments that reduce to general rules (EIP 1.3, 49–50; EIP 2.8, 120–1). Though operations of our intellectual powers are not definable or analyzable a priori, it is possible to describe the operations Reid has in mind.