Memoirs of Dr. Joseph Priestley

by Joseph Priestley

Dr. Hartley’s great work, (great, not from the bulk, but the importance of it) was first published in 1749. The direct and manifest tendency of the whole of his first volume is to destroy the common hypothesis of an immaterial soul: and this he does with a mass of fact and a force of reasoning irresistible. He shews clearly how all the faculties ascribed to the soul, thought, reflection, judgement, memory, and all the passions selfish and benevolent, may be resolved into one simple undeniable law of animal organization, without the necessity of any hypothesis such as that of a separate soul. Yet he does not appear distinctly to have seen the full weight and tendency of his own reasoning, and he adopts a theory on the subject, loaded with more difficulties and absurdities, than even the common hypothesis.

In 1757 was published a philosophical and scriptural inquiry into the nature and constitution “of mankind considered only as rational beings, wherein the antient opinion asserting the human soul to be an immaterial, immortal and thinking substance is found to be quite false and erroneous, and the true nature state and manner of existence of the power of thinking in mankind is evidently demonstrated by reason and the sacred scriptures.” Author J. R. M. I. Who this author really was I know not. But from the perusal of his book it is probable that he was a physician, and had been travelling. The above work he terms the philosophic or first part, and refers to a longer work of his own in manuscript which it seems he could not procure to be published. There is very little new in the book so far as I could judge.

I do not recollect any other treatise relating to the subject that excited public attention in England. In France and Holland La Mettrie began the controversy by his Histoire naturelle de L’Ame, published at the Hague in 1745 as a translation from the English of Mr. Charp;[66] it is a book containing many forcible remarks, and did credit to the side of the question which La Mettrie had adopted. Soon after this La Mettrie published L’Homme machine which was burnt in Holland in 1748. This was an honour not due to the formidable character of the work itself, which though it contains some of the common arguments drawn from the physiology and pathology of the human system, is by no means of first rate merit. He whimsically attributes the fierceness of the English, to their eating their meat more raw than other nations. This book was translated and published in London in 1750.

[66] This is probably one of the innumerable instances of the carelessness of French authors in quoting English names. La Mettrie most likely meant to ascribe this to Mr. Sharp the Surgeon, with whose reputation he must have been acquainted. I remember Arthur Young Esq. in one of his annals of agriculture complains that a paper of his translated into French was given to Artor Jionge ecuier. Some years ago Mr. Charles Taylor of Manchester (lately secretary to the society of Arts in London) was requested by Lord Hawkesbury to make some experiments to ascertain the value of East India Indigo when compared with the Spanish. Mr. Taylor did ascertain that the former yielded more colour for the same money at the current prices than the latter by above one fourth. In a paper I believe by M. D’Ijonval these experiments are quoted in a note as made by Le Chevalier Charles Tadkos celebre manufacturier de Manchester.

From Mr. Hallet’s discoveries the last volume of which was published in 1736 Dr. Priestley has extracted for himself and quoted what he deemed necessary on this question. I do not notice as part of the history of the question Materialism in England, the foreign atheistical publications, such as Le Systeme de la nature attributed to Mirabeau the father, Le vrai sens du Systeme de l’univers a posthumous work ascribed to Helvetius, Le Bon Sens by Meslier, and others whose titles do not now occur to me, because until within these few years, they were hardly known in England, and excited no discussion of the subject there, previous to the work of Dr. Priestley now under consideration.

The Doctor himself says in his preface to the disquisitions on matter and spirit, first published in 1777, that though he had entertained occasional doubts on the intimate union of two substances, so entirely heterogeneous as the Soul and the Body, the objections to the common hypothesis, did not impressively occur to him, until the publication of his treatise against the Scotch Doctors, which was in 1774. Those doubts indeed could hardly avoid occurring to any person who had carefully perused Hartley’s Essay on Man, first published in 1749, and Dr. Law’s appendix before mentioned in 1755.

Dr. Hartley has shewn with a weight of fact and argument amounting to demonstration, that all the phenomena of mind, may be accounted for from the known properties and laws of animal organization; and notwithstanding, that for some reason or other he has so far accommodated his work to vulgar prejudice, as to adopt the theory of a separate Soul, though in a very objectionable form, it is evidently a clog upon his system, and unnecessary to any part of his reasoning. Substitute Perception, and his theory is compleat. Nor indeed is it possible to reject this. Constant concomitance is the sole foundation on which we build out; inference of necessary connection: we have no evidence of the latter, but the former. Perception manifestly arises from, and accompanies animal organization; the facts are of perpetual occurrence, and the proof from induction is compleat.

Hartley having laid a sufficient foundation to conclude (as Dr. Priestley has done) that the natural appearances of the human system might be fully explained by means of Perception and Association, without the redundant introduction of the common hypothesis, Dr. Law a few years afterward compleatly proved to the christian world that though Life and Immortality were brought to light by the christian dispensation, the common theory of a separate immaterial and immortal soul, was not necessary to, or countenanced by the christian doctrine. Dr. Law seems by his preface, to have been fearful of the consequences of expressing the whole of his opinion on this abstruse subject, and confines himself in his appendix to the examination of the passages of Scripture usually referred to in favour of the Soul’s immortality. This appendix I believe was first added to the third edition of his Considerations on the Theory of Religion, published in 1755.

Against Dr. Priestley, any ground of popular obloquy would be eagerly laid hold of by the Bigots of the day. The doubts expressed in the examination of Drs. Reid, Oswald, and Beattie, excited so much obloquy, as to render it necessary for Dr. Priestley to review his opinions, and renounce or defend them. The result was, the disquisition on matter and spirit, the first volume containing a discussion of the question of materialism, the second that of liberty and necessity.

In discussing the former hypothesis, Dr. Priestley denies not only the existence of spirit as having no relation to extension or space, but also the common definition of matter, as a substance possessing only the inert properties of extension, and solidity or impenetrability. The latter he defines in conformity with the more accurate observations of later physics, a substance possessing the property of extension and the active powers of attraction and repulsion. With Boscovich and Mr. Michell, he admits of the penetrability of matter, and replies to the objections that may be drawn from this view of the subject.