attainment of this fcience? Moft certain-` ly they are: for whatever improves the fagacity of judgement, the fenfibility of moral perception, or the delicacy of tafte;' whatever renders our knowledge of moral and intellectual facts more extenfive; whatever impreffeth us with ftronger and more enlarged fentiments of duty, with more affecting views of God and Providence, and with greater energy of belief in the doctrines of natural religion;-every thing of this fort either makes us more thoroughly acquainted, or prepares us for becoming more thoroughly acquainted, with our own nature, with the nature of other beings, and with the relations that they and we bear to one another. But I fear we fhall not be able to improve ourselves in any one of these refpects, by reading the modern fyftems of fcepticifm. What account then are we to make of thofe fyftems, and their authors? The following differtation is partly defigned as an anfwer to this question. But it has a further view. It propofes to examine the foundations of this fcepticism, and to fee whether thefe be confiftent with what all mankind muft acknowledge to be

the

the foundations of truth; to inquire whether the cultivation of fcepticism be falutary or pernicious to fcience and mankind; and whether it may not be poilible to devife certain criteria, by which the abfurdity of its conclufions may be detected, even by thofe who may not have leifure, or fubtlety, or metaphyfical knowledge, fufficient to qualify them for a logical confutation of all its premifes. If it be confeffcd, that the prefent age hath fome tendency to licentioufnefs, both in principle and practice, and that the works of sceptical writers have fome tendency to favour that licentioufnefs; it will alfo be confeffed, that this defign is neither abfurd nor unfeasonable.

A celebrated writer on human nature hath obferved, that "if truth be at all "within the reach of human capacity, it "is certain it muft lie very deep and ab"ftrufe:" and a little after he adds, "that "he would efteem it a ftrong prefump"tion against the philofophy he is going "to unfold, were it fo very cafy and ob

*Treatife of Human Nature, vol. 1. p. 3. 4.

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"vious."

"vious." I am fo far from adopting this opinion, that I declare, in regard to the few things I have to fay on human nature, that I fhould esteem it a very strong prefumption against them, if they were not eafy and obvious. Phyfical and mathematical truths are often exceedingly abftrufe; but facts and experiments relating to the human mind, when expreffed in proper words, ought to be obvious to all. I find, that thofe poets, hiftorians, and novelifts, who have given the most lively difplays of human nature, and who abound most in fentiments easily comprehended, and readily admitted as true, are the most entertaining, as well as the most ufeful. How then fhould the philofophy of the human mind be fo difficult and obfcure? Indeed, if it be an author's determined purpofe to advance paradoxes, fome of which are incredible, and others incomprehenfible; if he be willing to avail hinfelf all he can of the natural ambiguity of language in fupporting those paradoxes; or if he enter upon inquiries too refined for human understanding; he muft often be obfcure, and often unintelligible. But my views are very different,

Ι

I only intend to fuggeft fome hints for guarding the mind against error; and thefe, I hope, will be found to be deduced from principles which every man of common capacity may examine by his daily experience.

It is true, that feveral fubjects of intricate fpeculation are examined in this book: but I have endeavoured, by conftant appeals to fact and experience, by illustrations and examples the most familiar I could think of, and by a plainnefs and perfpicuity of expreffion which fometimes may appear too much affected, to examine them in fuch a way, that I hope cannot fail to render them intelligible, even to those who are not much converfant in ftudies of this kind. Truth, like virtue, to be loved, needs only to be feen. My principles require no difguife; on the contrary, they will, if I mistake not, be moft easily admitted by those who beft understand them. And I am perfuaded, that the fceptical fyftem would never have made fuch an alarming progrefs, if it had been well understood. The ambiguity of its language, and the intricacy and length of

fome

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fome of its fundamental investigations, have unhappily been too fuccefsful in producing that confufion of thought, and indiftin&tnefs of apprehenfion, in the minds both of authors and readers, which are fo favourable to error and fophiftry.

Few men have ever engaged in controverfy, religious, political, or philofophical, without being in fome degree chargeable with mifconception of the adverfary's meaning. That I have never erred in this way, I dare not affirm. But I am confcious of having done every thing in my power to guard against it. The greater part of thefe papers have lain by me for feveral years; they have been repeatedly perufed by fome of the acuteft philofophers of the age, whom I have the honour to call my friends, and to whofe advice and affiftance, on this, as on other occafions, I am deeply indebted. I have availed myfelf all I could of reading and converfation; and endeavoured, with all the candour I am mafter of, to profit by every hint of improvement, and to examine to the bottom every objection, that others have offered, or myself could devife. And

may