Page:Essays on the Principles of Human Action (1835).djvu/129

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HARTLEY AND HELVETIUS.
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would equally follow from the same impression in any other circumstances, and ought to follow from any other idea partaking of the same general nature and properties. The proper effects of association can only apply to those cases, where an impression or idea by being associated with another has acquired a power of exciting actions to which it was itself perfectly indifferent. But this power cannot always be transferred from one impression to another, for there must be some original impression which has an inherent independent power to produce action.

I do not know how far the rules of philosophizing laid down by Sir Isaac Newton apply to the question, but it appears to me an evident conclusion of common sense not to seek for a remote and indirect cause of any effect where there is a direct and obvious one. Whenever therefore a particular action follows a given impression, if there is nothing in the impression itself incompatible with such an effect, it seems an absurdity to go about to deduce that action from some other impression, which has no more right to it's production than that which is immediately and obviously connected with it. In general it may be laid down as a principle of all sound reasoning, that where there are many things actually existing which may be assigned as the causes of several known effects, it is best to divide those effects among them, not arbitrarily to lay the whole weight of a complicated series of effects on the shoulders of some one of them, generally singled out for no other reason than because it is the most remote and therefore the least probable. For this there can be no more reason than for my supposing that when I see a large building standing on a number of pillars, the whole of it is secretly upheld by some main pillar in the centre, and that all the other pillars stand there merely for shew. The principle that the fewest causes