"It is a common observation, (and I think has great probability on its side,) that fools, weak or stupid persons, heavy and dull souls, are seldom much troubled with vapours or lowness of spirits. The intellectual faculty, without all manner of doubt, has material and animal organs, by which it mediately works, as well as the animal functions. What they are, and how they operate, as I believe very few know, so it is very little necessary to know them for my present purpose. As a philosophical musician may understand proportions and harmony, and yet never be in a condition to gratify a company with a fine piece of music, without the benefit of sounds from proper organs, so the intellectual operations (as long as the present union between soul and body lasts) can never be performed in the best manner without proper instruments. The works of imagination and memory, of study, thinking, and reflecting, from whatever source the principle on which they depend springs, must necessarily require bodily organs. Some have these organs finer, quicker, more agile, and sensible, and perhaps more numerous than others; brute animals have few or none, at least none that belong to reflection;
vegetables certainly none at all. There is no account to be given how a disease, a fall, a blow, a debauch, poisons, violent passions, astral and aerial influences, much application, and the like, should possibly alter or destroy these intellectual operations without this supposition. It is evident, that in nervous distempers, and a great many other bodily diseases, these faculties and their operations are impaired, nay, totally ruined and extinguished to all appearance; and yet, by proper remedies, and after recovery of health, they are restored and brought to their former state. Now, since this present age has made efforts to go beyond former times, in all the arts of ingenuity, invention, study, learning, and all the contemplative and sedentary professions, (I speak only here of our own nation, our own times, and of the better sort, whose chief employments and studies these are,) the organs of these faculties being thereby worn and spoiled, must affect and deaden the whole system, and lay a foundation for the diseases of lowness and weakness. Add to this, that those who are likeliest to excel and apply in this manner, are most capable and most in hazard of following that way of life which I have mentioned, as the likeliest to produce these diseases. Great wits are generally great epicures, at least, men of taste. And the bodies and constitutions of one generation are still more corrupt, infirm, and diseased, than those of the former, as they advance in time and the use of the causes assigned."
Then there are the farther coincidences, that Cheyne was a Scotsman, that he was an eminent man in his profession, and that he had bestowed some attention on mental philosophy. "I passed my youth," he tells us, "in close study, and almost constant application to the abstracted sciences, wherein my chief pleasure
consisted." "Having," he elsewhere says, "had a liberal education, with the instruction and example of pious parents, (who at first had designed me for the church,) I had preserved a firm persuasion of the great and fundamental principles of all virtue and morality: viz. the existence of a supreme and infinitely perfect Being, the freedom of the will, the immortality of the spirits of all intellectual beings, and the certainty of future rewards or punishments. These doctrines I had examined carefully, and had been confirmed in, from abstracted reasonings, as well as from the best natural philosophy, and some clearer knowledge of the material system of the world in general, and the wisdom, fitness, and beautiful contrivance of particular things animated and inanimated; so that the truth and necessity of these principles was so riveted in me, (which may be seen by the first edition of my 'Philosophical Principles,' published some years before that happened,[45:1]) as never after to be shaken in all my wanderings and follies."[45:2] It may
be mentioned also, as a circumstance likely to bring Cheyne's work early under Hume's observation, that it contains a long statement of the case of Dr. William
Cranstoun, an eminent medical man then residing at Jedburgh, in the same district of country with Ninewells.
FOOTNOTES:
[1:1] Old Style.
[1:2] He is entered in the list of members on 23d June, 1705, as "Mr. Joseph Hume of Ninewalls." It thus appears that the orthography of the name adopted by his son, and which will be found to have been so much the subject of dispute, was not a novelty to the family.