bound together by some universal principle, which had an equal influence on all mankind.

Though it be too obvious to escape observation, that different ideas are connected together; I do not find, that any philosopher has attempted to enumerate or class all the principles of association; a subject, however, that seems worthy of curiosity. To me, there appear to be only three principles of connection among ideas, namely, Resemblance, Contiguity in time or place, and Cause or Effect.

That these principles serve to connect ideas will not, I believe, be much doubted. A picture naturally leads our thoughts to the original *: The mention of one apartment in a building naturally introduces an inquiry or discourse concerning the others + And if we think of a wound, we can scarcely forbear reflecting on the pain which follows it. But that this enumeration is combab plete, and that there are no other principles of associa tion except these, may be difficult to prove to the satis faction of the reader, or even to a man's own satisface tion. All we , in such cases, is to run over seve ral instances, and examine carefully the principle which binds the different thoughts to each other, never stopping till we render the principle as general as possible §. The more instances we examine, and the more care we

can

employ, the more assurance, shall we acquire, that the enumeration, which we form from the whole, is com complete and

1690 Thure1 1979 10i binow Ɑious pa

*Resemblaficél ban54 Contiguity. Cause and Effect. $ For instance, Contrast or Contrariety is also a connection among deas: But it may, perhaps, be considered as a mixture of Causation and Resemblance. Where two objects are contrary, the oue destroys the other that is, the cause of its annihilation, and the idea of the annihilation of an object, implies the idea of its forther existence. latte 21 Jost 10123160

ALL the objects of human reason or inquiry may naturally be divided into two kinds, to wit, Relations of Ideas, and Matters of Fact, Of the first kind are the sciences of Geometry, Algebra, and Arithmetic; and in short, every affirmation which is either intuitively or demonstratively certain. That the square of the hypothenuse is equal to the square of the two sides, is a proposition which expresses a relation between these figures. That three times five is equal to the half of thirty, expresses a relation between these numbers. Propositions of this kind are discoverable by the mere operation of thought, without dependence on what is any where existent in the universe. Though there never were a circle or triangle in nature, the truths demonstrated by EUCLID would for ever retain their certainty and evidence.

Matters of fact, which are the second objects of hu

man fea

reason, are not ascertained in the same manner; non is our evidence of their truth, however great, of a like nature with the foregoing. The The contrary of every matter of fact is still possible, because it can never im

ply a contradiction, and is conceived by the mind with the same facility and distinctness, as if ever so conformable to reality. That the sun will not rise to-morrow, is no less intelligible a proposition, and implies no more contradiction than the affirmation, that it will rise. We should in vain, therefore, attempt to demonstrate its falsehood. Were it demonstratively false, it would imply a contradiction, and could never be distinctly conceived by the mind.

It may therefore be a subject worthy of curiosity, to inquire what is the nature of that evidence, which assures us of any real existence and matter of fact, beyond the present testimony of our senses, or the records of our memory. This part of philosophy, it is observable, has been little cultivated, either by the ancients or moderns; and therefore our doubts and errors, in the prosecution of so important an inquiry, may be the more excusable, while we march through such difficult paths without any guide or direction. They may even prove useful, by exciting curiosity, and destroying that impli cit faith and security which is the bane of all reasoning and free inquiry. The discovery of defects in the common philosophy, if any such there be, will. not, I presume, be a discouragement, but rather an incitement, as is usual, to attempt something more full and satisfactory than has yet been proposed to the public

-All reasonings concerning matter of fact seem to be founded on the relation of Cause and Effect. By means of that relation alone we can go beyond the evidence of our memory and senses. If you were to ask a man, why he believes any matter of fact which is absent; for instance, that his friend is in the country, or in FRANCE; the would give you a reason wand this reason would be some other facti nsa letter received from him, or the of row 1 teda zotew? You216qam bas zbu

2

knowledge of his former resolutions and promises. A man, finding a watch or any other machine in a desart island, would conclude that there had once been men in that island. All our reasonings concerning fact are of the same nature. And here it is constantly supposed, that there is a connection between the present fact and that which is inferred from it. Were there nothing to bind them together, the inference would be entirely precarious. The hearing of an articulate voice and ration al discourse in the dark, assures us of the presence of some person: Why? because these are the effects of the human make and fabric, and closely connected with it. If we anatomize all the other reasonings of this na ture, we shall find, that they are founded on the rela tion of cause and effect, and that this relation is either near or remote, direct or collateral. Heat and light are collateral effects of fire, and the one effect may justly be inferred from the other.

If we would satisfy ourselves, therefore, concerning the nature of that evidence which assures us of matters of fact, we must inquire how we arrive at the knowledge of cause and effect.

I shall venture to affirm as a general proposition, which admits of no exception, that the knowledge of this relation is not, in any instance, attained by reasonings a priori; but arises entirely from experience, when we find, that any particular objects are constantly conjoined with each other. Let an object be presented to a man of ever so strong natural reason and abilities; if that object be entirely new to him, he will not be able, by the most accurate examination of its sensible qualities, to discover any of its causes or effects. ADAM, though his rational faculties be supposed, at the very first, entirely perfect, could not have inferred from the fluidity and transparency of water, that it would suffo

cate him; or from the light and warmth of fire; that it would consume him. No object ever discovers, by the qualities which appear to the senses, either the causes which produced it, or the effects which will arise from it; nor can our reason, unassisted by experience, ever draw any inference concerning real existence and matter of fact.

This proposition, that causes and effects are discoverable, not by reason, but by experience, will readily be admitted with regard to such objects as we remember to have once been altogether unknown to us; since we must be conscious of the utter inability which we then lay under of foretelling what would arise from them. Present two smooth pieces of marble to a man who has no tincture of natural philosophy; he will never discover that they will adhere together in such a manner as to require great force to separate them in a direct line, while they make so small a resistance to a lateral pressure. Such events as bear little analogy to the common course of nature, are also readily confessed to be known only by experience; nor does any man imagine that the explosion of gunpowder, or the attraction of a loadstone, could ever be discovered by arguments a priori. In like manner, when an effect is supposed to depend upon an intricate machinery or secret structure of parts, we make no difficulty in attributing all our knowledge of it to experience. Who will assert, that he can give the ultimate reason, why milk or bread is proper nourishment for a man, not for a lion or a tiger?

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But the same truth may not appear at first sight to have the same evidence with regard to events, which have become familiar to us from our first appearance in the world, which bear a close analogy to the whole course of nature, and which are supposed to depend on the sim