nature--is far larger than its subjective existence--_i.e._ than its mode of existing _quoad_ some particular subject. A being more limited than man might be so framed as to be unable to conceive curve lines; but this subjective inaptitude for those determinations of space would not affect the objective reality of curves, or even their subjective reality for a higher intelligence. Thus, on the hypothesis of an objective existence for space, we should be thrown upon an ocean of possibilities, without a test for saying what was--what was not possible. But, on the other hypothesis, having always in the last resort what is _subjectively_ possible or impossible (_i.e._ what is conceivable or not by us, what can or cannot be drawn or circumscribed by a human imagination), we have the means of demonstration in our power, by having the ultimate appeals in our power to a known uniform test--viz. a known human faculty. This is no trifling matter, and therefore no trifling advantage on the side of Kant and his philosophy, to all who are acquainted with the disagreeable controversies of late years among French geometricians of the first rank, and sometimes among British ones, on the question of mathematical evidence. Legendre and Professor Leslie took part in one such a dispute; and the temper in which it was managed was worthy of admiration, as contrasted with the angry controversies of elder days, if, indeed, it did not err in an opposite spirit, by too elaborate and too calculating a tone of reciprocal flattery. But, think as we may of the discussion in this respect, most assuredly it was painful to witness so infirm a philosophy applied to an interest so mighty. The whole aerial superstructure--the heaven-aspiring pyramid of geometrical synthesis--all tottered under the palsying logic of evidence, to which these celebrated mathematicians appealed. And wherefore?--From the want of any philosophic account of space, to which they might have made a common appeal, and which might have so far discharged its debt to truth as at least to reconcile its theory with the great outstanding phenomena in the most absolute of sciences. Geometry is the _science_ of space: therefore, in any _philosophy_ of space, geometry is entitled to be peculiarly considered, and used as a court of appeal. Geometry has these two further claims to distinction--that, 1st, It is the most perfect of the sciences, so far as it has gone; and, 2dly, That it has gone the farthest. A philosophy of space which does not consider and does not reconcile to its own doctrines the facts of geometry, which, in the two points of beauty and of vast extent, is more like a work of nature than of man, is, _prima facie_, of no value. A philosophy of space _might_ be false which should harmonize with the facts of geometry--it _must_ be false if it contradict them. Of Kant's philosophy it is a capital praise that its very opening section--that