Every instant in Time is conditioned by the preceding one. The Sufficient Reason of Being, as the law of consequence, is so simple here, because Time has only one dimension, therefore it admits of no multiplicity of relations. Each instant is conditioned by its predecessor; we can only reach it through that predecessor: only so far as this _was_ and has elapsed, does the present one exist. All counting rests upon this nexus of the divisions of Time, numbers only serving to mark the single steps in the succession; upon it therefore rests all arithmetic likewise, which teaches absolutely nothing but methodical abbreviations of numeration. Each number pre-supposes its predecessors as the reasons of its being: we can only reach the number _ten_ by passing through all the preceding numbers, and it is only in virtue of this insight that I know, that where ten are, there also are eight, six, four. § 39. _Geometry._ The whole science of Geometry likewise rests upon the nexus of the position of the divisions of Space. It would, accordingly, be an insight into that nexus; only such an insight being, as we have already said, impossible by means of mere conceptions, or indeed in any other way than by intuition, every geometrical proposition would have to be brought back to sensuous intuition, and the proof would simply consist in making the particular nexus in question clear; nothing more could be done. Nevertheless we find Geometry treated quite differently. Euclid's Twelve Axioms are alone held to be based upon mere intuition, and even of these only the Ninth, Eleventh, and Twelfth are properly speaking admitted to be founded upon different, separate intuitions; while the rest are supposed to be founded upon the knowledge that in science we do not, as in experience, deal with real things existing for themselves side by side, and susceptible of endless variety, but on the contrary with conceptions, and in Mathematics with _normal intuitions_, i.e. figures and numbers, whose laws are binding for all experience, and which therefore combine the comprehensiveness of the conception with the complete definiteness of the single representation. For although, as intuitive representations, they are throughout determined with complete precision--no room being left in _this_ way by anything remaining undetermined--still they are general, because they are the bare forms of all phenomena, and, as such, applicable to all real objects to which such forms belong. What Plato says of his Ideas would therefore, even in Geometry, hold good of these normal intuitions, just as well as of conceptions, _i.e._ that two cannot be exactly similar, for then they would be but one.[148] This would, I say, be applicable also to normal intuitions in Geometry, if it were not that, as exclusively spacial objects, these differ from one another in mere juxtaposition, that is, in place. Plato had long ago remarked this, as we are told by Aristotle:[149] ἔτι δὲ, παρὰ τὰ αἰσθητὰ καὶ τὰ