Principal Pollock of Marischal College died in 1759, and it was supposed at the time that the chance of succeeding him was confined to two gentlemen possessed of all the local influence which in such cases generally insures success. Mr Campbell, who was ambitious of obtaining the situation, resolved to lay his pretensions before the duke of Argyle, who, for many years, had dispensed the government patronage of Scotland. It happened that one of Mr Campbell's ancestors, his grandfather or great-grandfather, had held the basket into which the marquis of Argyle's head fell when he was. beheaded. Mr Campbell hinted at this in the letter he addressed to his grace; and the result was his appointment to the vacant place. This anecdote, we need scarcely remind the reader, has been lately used in fictitious history.
Shortly after this Mr Campbell received the degree of doctor of divinity from King's College, Aberdeen; and, in 1763, he published his celebrated "Treatise on Miracles," in answer to what was advanced on that subject by David Hume; a work which has been justly characterised as one of the most acute and convincing treatises that has ever appeared upon the subject.
A condensed view of the respective arguments of these two philosophers, on one of the most interesting points connected with revealed religion, is thus given by the ingenious William Smellie, in the first edition of the Encyclopedia Britannica, under the article Abridgment: —
Mr Hume argues, "That experience, which, in some things is variable, in others uniform, is our only guide in reasoning concerning matters of fact. A variable experience gives rise to probability only; a uniform experience amounts to a proof. Our belief of any fact from the testimony of eye-witnesses is derived from no other principle than our experience in the veracity of human testimony. If the fact attested be miraculous, here arises a contest of two opposite experiences, or proof against proof. Now, a miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as complete as any argument from experience can possibly be imagined; and, if so, it is an undeniable consequence, that it cannot be surmounted by any proof whatever derived from human testimony.
Dr Campbell, in his answer, aims at showing the fallacy of Mr Hume's argument by another single position. He argues, " That the evidence arising from human testimony is not solely derived from experience; on the contrary, testimony hath a natural influence on belief, antecedent to experience. The early and unlimited assent given to testimony by children gradually contracts as they advance in life : it is, therefore, more consonant to truth, to say, that our diffidence in testimony is the result of experience, than that our faith in it has this foundation. Besides, the uniformity of experience, in favour of any fact, is nit a proof against its being reversed in a particular instance. The evidence arising from the single testimony of a man of known veracity will go far to establish a belief in its being actually reversed: If his testimony be confirmed by a few others of the same character, we cannot withhold our assent to the truth of it. Now, though the operations of nature are governed by uniform laws, and though we have not the testimony of our senses in favour of any violation of them, still, if, in particular instances, we have the testimony of thousands of our fellow-creatures, and those, too, men of strict integrity, swayed by no motives of ambition or inteiest, and governed by the principles of common sense, That they were actual eye-witnesses of these violations, the constitution of our nature obliges us to believe them."
Dr Campbell's essay was speedily translated into the French, Dutch, and German languages.
