“The knowledge concerning the sympathies and concordances between the mind and the body” saith the founder† of modern science, in discoursing of human philosophy, or the knowledge of ourselves, as he terms it, is “fit to be emancipate and made a knowledge by itself. The consideration is double: either how and how far the humours and effects of the body do alter or work upon the mind; or again, how and how far the passions and apprehensions of the mind do alter or work upon the body. The former of these,” (the influence of the body on the mental state,) continues Bacon, “hath been enquired and considered as a part and appendix of medicine, but much more as a part of religion or superstition. For the physician prescribeth cures of the mind in phrensies and melancholy passions; and pretendeth also to exhibit medicines to exhilarate the mind, to confirm the courage, to clarify the wits, to corroborate the memory and the like: but the scruples and superstitions of diet and other regimen of the body in the sect of Pythagoreans, in the heresy of the Manicheans, and in the law of Mahomet do exceed. … The root and life of all which prescripts is besides the ceremony, the consideration of that dependency, which the affections of the mind are submitted unto, upon the state and disposition of the body.”

Lord Bacon, after pointing out the obvious correspondence which exists between the feelings, and particular expressions and gestures, goes on to say, “But unto all this knowledge de communi vinculo, of the concordance between the mind and the body, that part of the enquiry is most necessary, which considereth of the seats and domiciles, which the several faculties of the mind do take and occupate in the organs of the body; which knowledge hath been attempted, and is controverted, and deserveth to be much better inquired into.”

It would seem rather superfluous to remark, that no science can be definite or precise, whose terms are undefined and inexact, and that it behoves the student in any science, to understand the terms employed, before he can master his subject; more especially is this the case, where the subject treats of abstract qualities and ideas, whose fundamental terms, themselves expressing abstracts, require defining from the very beginning: and yet, the difficulty I have met with, and which others have experienced in those terms which form the subject of the following remarks, will perhaps shew that such precision is not so universally observed as is supposed.