Inquiry into our conception of Power or Causation becomes prominent in Reid’s letters to Lord Kames throughout ‘the seventies,’ along with experimental investigations in physics and physiology which show continued interest in natural causes. A letter, written in 1775, contains a curious conjecture with regard to the generation of plants and animals, more speculative than was his habit. He is ‘apt to conjecture,’ he tells his friend, ‘that both plants and animals are at first organised atoms, having all the parts of the animal or plant, but so slender, and folded up in such a manner, as to be reduced to a particle far beyond the reach of our senses, and perhaps as small as the constituent parts of water. The earth, the water, and the air may, for anything I know, be full of such organised atoms.’ He then goes on to consider the relation of this hypothesis to the idea of active design in nature, and expresses doubt about the possibility of the atoms being endowed with power to form themselves into an organised body like the human. ‘I cannot help thinking that such a work as the Iliad, and much more an animal or vegetable body, must have been made by express design. It seems to me as easy to contrive a machine which should compose a variety of epic poems and tragedies, as to contrive laws of motion by which unthinking particles of matter should coalesce into a variety of organised bodies.’ He suggests that the organisation is the issue of constant and uniform divine activity. ‘Can we,’ he asks, ‘show by any good reason that the Almighty finished his work at a stroke, and has continued ever since an inactive spectator? And if His continued operation be necessary, it is no miracle, while it is uniform, and according to fixed laws. Though we should suppose the gravitation of matter to be the immediate operation of the Deity, it would be no miracle while it is constant and uniform; but if it should cease for a moment, only by His withholding His hand, this would be a miracle.’ This is to say that all natural changes are immediate effects of divine action, proceeding according to natural law or rule.
The suggestion illustrates the bent of Reid’s thought in later life. If our common sense of the continuous independent existence of sensible things, and of their manifestation in Perception as directly as states of our own minds are manifested to us when we are conscious of them—if this was the factor of the Common Sense that engaged him in New Machar and King’s College days, the Power or Causality which all changes in the universe presuppose now becomes prominent, alike in his correspondence and in his books. What is meant by Power, and where is the Power centred that is implied in the changes that are always going on, in ourselves and in our surroundings? Priestley’s assumption that matter explains all the phenomena of a human mind; the theory of universal necessity advocated by Kames; and the duties of his Glasgow professorship, all tended to carry his reflections onward from the merely physical to the ethical judgments of the common sense, and so upward from the merely natural to the spiritual interpretation of the universe. ‘First that which is natural, then that which is spiritual.’
This runs through his correspondence with Lord Kames. That there is no absolute necessity for men being bad; that their immoral acts are centred and originate in themselves and not in God; that it would be unjust to exact as a duty what it is not in a person’s power to do; that what a man does voluntarily or with deliberate intention, it is also in his power not to do; that what is done without his will is not really done by him at all; and that real power is moral agency,—these are ultimate judgments, reached ‘not by logical reasoning,’ but in ‘the more trustworthy way of immediate perception and feeling,’ to which Reid so often appeals. ‘If I could suppose God to make a devil a devil, I cannot suppose that He would condemn him for being a devil,’ is in a letter to Lord Kames.[21] The impotence of matter rather than its independence is now insisted on; with the inference that at any rate it cannot cause our perceptions, as Priestley supposed. He begins to see that power must be referred to mind or spirit alone, and that matter is powerless. ‘Efficient causes are not within the sphere of natural philosophy, which is concerned only with the laws or methods according to which Power operates. It exhibits the grand machine of the material world, analysed, as it were, and taken to pieces. It belongs to metaphysics and natural theology to show the Power that continues and gives motion to the whole; according to laws which the naturalist discovers, and perhaps according to laws still more general.’
It was thus that Reid’s uneventful life of thought—deep, steady, unobtrusive—was sustained for sixteen years, when he was educating the rising generation in the old class-room at the College; unfolding philosophy in correspondence with a sympathetic friend; contributing essays to the Literary Society which met monthly at the College; and preparing his ‘Brief Account’ of Aristotle—all until he had reached his seventieth year. On the 19th of May 1780 he wrote to Lord Kames of a change that had occurred the day before:—
‘I find myself growing old; and I have no right lo plead exemption from the infirmities of that stage of life. For that reason I have made choice of an Assistant in my office. Yesterday the College at my desire made choice of Mr. Archibald Arthur, preacher, to be my assistant and successor. I think I have done good service to the College by this, and procured some leisure to myself, though with reduction of my finances.’
It was Reid’s desire, while his faculties were yet vigorous, to devote his strength to further philosophical authorship. During the remaining sixteen years of his life his lectures were delivered to the students by Mr. Arthur, to whom the professorial work in the class-room was transferred. Arthur, then thirty-six years of age, was a native of Renfrewshire, a distinguished alumnus of Glasgow, as it seems from a posthumous volume of his Essays, and a man not unlike Reid in mind and character, but in inferior form; at this time chaplain and librarian of the University, and a member of the Literary Society. After one of Arthur’s Sunday services in the College chapel, Reid had whispered to one of his colleagues on the professorial bench—‘This is a very sensible fellow, and in my opinion would make a good professor of morals.’[22] He is described by a contemporary as ‘a man of unprepossessing exterior, of invincible bashfulness, which continued to clog his manner and impede his exertions during the whole course of his life; but of a thoughtful, grave, silent habit, which led him to a due estimate of what he was individually adapted to.’ He survived Reid, as his successor, a little more than a year, when he was followed in the Chair by James Mylne, a strong man unknown in philosophical literature, whose professorial career of forty years made him a familiar figure to generations of Glasgow students.
CHAPTER VII
PHILOSOPHICAL RETIREMENT: AUTHORSHIP IN OLD AGE
1780-1795
Dugald Stewart, when illustrating the changes in human memory that are connected with disease and old age, refers thus to Reid:—‘One old man I have myself had the good fortune to know, who, after a long, an active, and an honourable life, having begun to feel some of the usual effects of advanced years, has been able to find resources in his own sagacity against most of the inconveniences with which they are commonly attended; and who, by watching his gradual decline with the courage of an indifferent observer, and employing his ingenuity to retard its progress, has converted even the infirmities of old age into a source of philosophical amusement.’ For sixteen years Reid had been discharging that part of the duties of a professor which belongs to the class-room: the remaining sixteen years of his life, devoted to original research and authorship, illustrate the words of Stewart. He continued, after the appointment of Arthur, to live as before in the Professors’ Court in old Glasgow College—a placid, methodical life, steadily industrious, a sagacious interpreter of nature and of man, still active in the academic senate—with occasional recreation in visits to the country. The year 1780 was saddened by another of those domestic sorrows which formed the chief interruption to the tranquil happiness of his life; for his eldest son, George, died in Newfoundland in February, at the age of twenty-five. Two years later the only remaining son, David, was taken away; after which his daughter, Mrs. Carmichael, alone survived of the nine sons and daughters.