Clark devotes chapter 7 of "The Lord God of Truth" to attacking the reliance of empiricism upon imagination. He identifies Aristotle as both the first and best philosopher to have dealt exhaustively with a philosophical account of images. Imagination functions, it is supposed, by retaining the memory of a sensation. Apart from images, Clark notes, empiricism cannot function at all:
Perhaps the most definite defense of imagination in modern times was that of David Hume, who convenietly died in 1776 so Americans could most easily remember him. In his Treatise of Human Nature he started out, right on page one, by distinguishing impressions (sensations) from ideas (memory images). "Those perceptions which enter with most force and violence we may name impressions ... sensations, passions, and emotions....By ideas I mean the faint images of these in thinking and reasoning""(Clark)
Thus, Clark quotes Hume to show that for Hume, we acquire knowledge through sensation, and these images are stored in our minds in the form of "ideas" or memories of these sensations. Any impression, for Hume, has an idea which corresponds with it. Clark denies, however, that something like the impression of red, produces an "idea." Likewise, following the event of hearing a musical composition, we no longer have an "idea" of a tone. The same is likewise true of taste. Clark refers to Russell's reference to the insanity of the person who denies that he has images, and Clark confesses that he himself must be mad because he lacks such ideas. Since Clark's own experience contradicts theirs, he points out that his very own lack of a parallel experience disproves them. "Let them talk about themselves, if they can do so legitimately; but their experience gives them no knowledge of mine"(Clark, p. 29). Indeed, Clark points out on p. 32 that it is well-known that many famous scientists had no concept of mental imagery.
Clark then cites Binet's understanding of the relation of sensation to knowledge, and repudiates it as circular and self-refuting:
He first granted that the aggragate of our sensations is all we can know about the exterior world; and now to make it more definite he "can rightly define the latter as the collection of our present, past and possible sensations." Therefore, if there be any exterior world at all, we have no knowledge of it, for our sensations themselves are all we know. In particular no one can know that there are any sense organs, or any stimuli, or any action on the nerves. Yet...he speaks of "perceiving an exterior object." Why did he not perceive this contradiction?(Clark, p. 30)
Clark concludes that the rest of Binet's writings on sensation have a rotten foundation, and fall because of it. He states that his desire is to develop an apologetics that is able to defeat secularism, and sees the development of a correct epistemology as essential to such a desire. Likewise, he wants to point out that secularists tend to rely upon sensation, and that relying upon sensation for one's theory of knowledge results in a self-refuting epistemology.
Clark, Gordon. "Lord God of Truth." The Trinity Foundation, 1986. Hobbes, New Mexico.