"To this we reply, that these truths can only be known to be _general_, not universal, if they depend upon experience alone. Experience cannot bestow that universality which she herself cannot have, and that necessity of which she has no comprehension. If these doctrines are universally true, this universality flows from the _ideas_ which we apply to our experience, and which are, as we have seen, the real sources of necessary truth. How far these ideas can communicate their universality and necessity to the results of experience, it will hereafter be our business to consider. It will then appear, that when the mind collects from observation truths of a wide and comprehensive kind, which approach to the simplicity and universality of the truths of pure science; she gives them this character by throwing upon them the light of her own fundamental ideas."--_Whewell_, Vol. I. p. 60. Accordingly, Mr Whewell no sooner arrives at any truth which admits of an unconditional positive statement--a statement defying all rational contradiction--than he abstracts it from amongst the acquisitions of experience, and throwing over it, we suppose, the light of these fundamental ideas, pronounces it enrolled in the higher class of universal and necessary truths. The first laws of motion, though established through great difficulties against the most obstinate preconceptions, and by the aid of repeated experiments, are, when surveyed in their present perfect form, proclaimed to be, not acquisitions of experience, but truths emanating from a higher and more mysterious origin.[2] [2] Necessary truths multiply on us very fast. "We maintain," says Mr Whewell, "that this equality of _mechanical action and reaction_ is one of the principles which do not flow from, but regulate, our experience. A mechanical pressure, not accompanied by an equal and opposite pressure, can no more be given by experience than two unequal right angles. With the supposition of such inequalities, space ceases to be space, form ceases to be form, matter ceases to be matter." And again he says, "_That the parallelogram of forces is a necessary truth_;" a law of motion of which we surely can _conceive_ its opposite to be true. In some of these instances Mr Whewell appears, by a confusion of thought, to have given to the _physical fact_ the character of necessity which resides in the mathematical formula employed for its expression. Whether a moving body would communicate motion to another body--whether it would lose its own motion by so doing--or what would be the result if a body were struck by two other bodies moving in different directions--are questions which, if they could be asked us prior to experience, we could give no answer whatever to--which we can easily conceive to admit of a quite different answer to that which experience has taught us to give.