On the Vital Principle/Book 3/Prelude to Chapter 3
PRELUDE TO CHAPTER III.
This chapter may be regarded as a metaphysical disquisition, since its purport is to distinguish mental faculties from corporeal sensations as well as to examine the opinions of earlier writers who had maintained
that cogitation is some kind of sensation; and, finally, the nature of imagination, as lying intermediately between faculties and sensations, is investigated and defined. It treats, too, although but incidentally, of the understanding, knowledge, opinion, and other topics which border on abstractions; and closes with etymology to shew the sentient origin of imagination.