Rationalism distinguishes between empirical knowledge, i.e., knowledge that arises through experience, and a priori knowledge, i.e., knowledge that is prior to experience and that arises through reason. Empirical knowledge depends upon our senses, senses that, the rationalist wastes no time to demonstrate, are unreliable. Here the rationalist appeals to common sense deceptions and perceptual illusions.
Empiricism denies the rationalist distinction between empirical and a priori knowledge. All knowledge, the empiricist argues, arises through, and is reducible to, sense perception. Thus, there is no knowledge that arises through reason alone. Thus, empiricism credo is that where there is (or can be) no experience there is (and can be) no knowledge.
Thanks in advance.