This being so undeniably the case, the history of the way in which philosophy has dealt with it is curious. The ruling tradition in philosophy has always been the platonic and aristotelian belief that fixity is a nobler and worthier thing than change. Reality must be one and unalterable. Concepts, being themselves fixities, agree best with this fixed nature of truth, so that for any knowledge of ours to be quite true it must be knowledge by universal concepts rather than by particular experiences, for these notoriously are mutable and corruptible. This is the tradition known as rationalism in philosophy, and what I have called intellectualism is only the extreme application of it. In spite of sceptics and empiricists, in spite of Protagoras, Hume, and James Mill, rationalism has never been seriously questioned, for its sharpest critics have always had a tender place in their hearts for it, and have obeyed some of its mandates. They have not been consistent; they have played fast and loose with the enemy; and Bergson alone has been radical. To show what I mean by this, let me contrast his procedure with that of some of the transcendentalist philosophers whom I have lately mentioned. Coming after Kant, these pique themselves on being 'critical,' on building in fact upon Kant's 'critique' of pure reason. What that critique professed to establish was this, that concepts do not apprehend reality, but only such appearances as our senses feed out to them. They give immutable intellectual forms to these appearances, it is true, but the reality _an sich_ from which in ultimate resort the sense-appearances have to come remains forever unintelligible to our intellect. Take motion, for example. Sensibly, motion comes in drops, waves, or pulses; either some actual amount of it, or none, being apprehended. This amount is the datum or _gabe_ which reality feeds out to our intellectual faculty; but our intellect makes of it a task or _aufgabe_--this pun is one of the most memorable of Kant's formulas--and insists that in every pulse of it an infinite number of successive minor pulses shall be ascertainable. These minor pulses _we_ can indeed _go on_ to ascertain or to compute indefinitely if we have patience; but it would contradict the definition of an infinite number to suppose the endless series of them to have actually counted _themselves_ out piecemeal. Zeno made this manifest; so the infinity which our intellect requires of the sense-datum is thus a future and potential rather than a past and actual infinity of structure. The datum after it has made itself must be decompos_able_ ad infinitum by our conception, but of the steps by which that structure actually got composed we know nothing. Our intellect casts, in short, no ray of light on the processes by which experiences _get made_.