Click on the phrases to see them in context. The original texts by Immanuel Kant and David Hume are available from the Gutenberg Projet.

The one says; "You must philosophize upon nature," as if there existed a necessary primal basis of all existing things, solely for the purpose of introducing systematic unity into your knowledge, by pursuing an idea of this character--a foundation which is arbitrarily admitted to be ultimate; while the other warns you to consider no individual determination, concerning the existence of things, as such an ultimate foundation, that is, as absolutely necessary, but to keep the way always open for further progress in the deduction, and to treat every determination as determined by some other.

A plant, and animal, the regular order of nature--probably also the disposition of the whole universe--give manifest evidence that they are possible only by means of and according to ideas; that, indeed, no one creature, under the individual conditions of its existence, perfectly harmonizes with the idea of the most perfect of its kind- just as little as man with the idea of humanity, which nevertheless he bears in his soul as the archetypal standard of his actions; that, notwithstanding, these ideas are in the highest sense individually, unchangeably, and completely determined, and are the original causes of things; and that the totality of connected objects in the universe is alone fully adequate to that idea. The schema of reality is existence in a determined time. For, in order to make even internal change cognitable, we require to represent time, as the form of the internal sense, figuratively by a line, and the internal change by the drawing of that line (motion), and consequently are obliged to employ external intuition to be able to represent the successive existence of ourselves in different states. I answer; It is absurd to introduce--under whatever term disguised--into the conception of a thing, which is to be cogitated solely in reference to its possibility, the conception of its existence. That space and time are only forms of sensible intuition, and hence are only conditions of the existence of things as phenomena; that, moreover, we have no conceptions of the understanding, and, consequently, no elements for the cognition of things, except in so far as a corresponding intuition can be given to these conceptions; that, accordingly, we can have no cognition of an object, as a thing in itself, but only as an object of sensible intuition, that is, as phenomenon--all this is proved in the analytical part of the Critique; and from this the limitation of all possible speculative cognition to the mere objects of experience, follows as a necessary result. For this very permanence is the ground on which we apply the category of substance to the phenomenon; and we should have been obliged to prove that in all phenomena there is something permanent, of the existence of which the changeable is nothing but a determination.

The minor contains an experience, the major reasons from a general experience to the existence of a necessary being.* Thus this argument really begins at experience, and is not completely a priori, or ontological.

For it is evident our pains and pleasures, our passions and affections, which we never suppose to have any existence beyond our perception, operate with greater violence, and are equally involuntary, as the impressions of figure and extension, colour and sound, which we suppose to be permanent beings. According to this way of thinking, we ought not to receive as reasoning any of the observations we may make concerning identity, and the relations of time and .place; since in none of them the mind can go beyond what is immediately present to the senses, either to discover the real existence or the relations of objects.