As his mind was capacious, his curiosity excursive, and his industry continual, his writings are very numerous, and his subjects various. With his theological works I am only enough acquainted to admire his meekness of opposition, and his mildness of censure. It was not only in his book but in his mind that orthodoxy was united with charity.
Of his philosophical pieces, his Logic has been received into the universities, and therefore wants no private recommendation: if he owes part of it to Le Clerc, it must he considered that no man who undertakes merely to methodize or illustrate a system, pretends to be its author.
In his metaphysical disquisitions, it was observed by the late learned Dr. Dyer, that he confounded the idea of space with that of empty space, and did not consider that though space might be without matter, yet matter being extended, could not be without space.
Few books have been perused by me with greater pleasure than his Improvement of the Mind, of which the radical principles may indeed be found in Locke's Conduct of the Understanding, but they are so expanded and ramified by Watts, as to confer upon him the merit of a work in the highest degree useful and pleasing. Whoever has the care of instructing others, may be charged with deficience in his duty if this book is not recommended.
I have mentioned his treatises of Theology as distinct from his other productions: but the truth is, that whatever he took in hand was, by his incessant solicitude for souls, converted to Theology. As piety predominated in his mind, it is diffused over his works: under his direction it may be truly said, Theologiae Philosophia ancillatur, philosophy is subservient to evangelical instruction; it is difficult to read a page without learning, or at least wishing to be better. The attention is caught by indirect instruction, and he that sat down only to reason, is on a sudden compelled to pray.
It was therefore with great propriety that, in 1728, he received From Edinburgh and Aberdeen an unsolicited diploma, by which he became a Doctor of Divinity. Academical honours would have more value, if they were always bestowed with equal judgement.
He continued many years to study and to preach, and to do good by His instruction and example: till at last the infirmities of age disabled him from the more laborious part of his ministerial functions, and being no longer capable of public duty, he offered to remit the salary appendant to it; but his congregation would not accept the resignation.
By degrees his weakness increased, and at last confined him to his chamber and his bed; where he was worn gradually away without pain, till he expired, Nov. 25, 1748, in the seventy-fifth year of his age.
Few men have left behind such purity of character, or such monuments of laborious piety. He has provided instruction for all ages, from those who are lisping their first lessons, to the enlightened readers of Malbranche and Locke; he has left neither corporeal nor spiritual nature unexamined; he has taught the art of reasoning, and the science of the stars.
His character, therefore, must be formed from the multiplicity and diversity of his attainments, rather than from any single performance; for it would not be safe to claim for him the highest rank in any single denomination of literary dignity; yet perhaps there was nothing in which he would not have excelled, if he had not divided his powers to different pursuits.