| For the original apperception relates to our internal sense (the complex of all representations), and indeed relates a priori to its form, that is to say, the relation of the manifold empirical consciousness in time. |
| Now this manifold must be combined in original apperception according to relations of time--a necessity imposed by the a priori transcendental unity of apperception, to which is subjected all that can belong to my (i.e., my own) cognition, and therefore all that can become an object for me. |
| This synthetical and a priori determined unity in relation of perceptions in time is therefore the rule; "All empirical determinations of time must be subject to rules of the general determination of time"; and the analogies of experience, of which we are now about to treat, must be rules of this nature. |
| These principles have this peculiarity, that they do not concern phenomena, and the synthesis of the empirical intuition thereof, but merely the existence of phenomena and their relation to each other in regard to this existence. |
| Now the mode in which we apprehend a thing in a phenomenon can be determined a priori in such a manner that the rule of its synthesis can give, that is to say, can produce this a priori intuition in every empirical example. |
| But the existence of phenomena cannot be known a priori, and although we could arrive by this path at a conclusion of the fact of some existence, we could not cognize that existence determinately, that is to say, we should be incapable of anticipating in what respect the empirical intuition of it would be distinguishable from that of others. |
| The two principles above mentioned, which I called mathematical, in consideration of the fact of their authorizing the application of mathematic phenomena, relate to these phenomena only in regard to their possibility, and instruct us how phenomena, as far as regards their intuition or the real in their perception, can be generated according to the rules of a mathematical synthesis. |
| Consequently, numerical quantities, and with them the determination of a phenomenon as a quantity, can be employed in the one case as well as in the other. |
| Thus, for example, out of 200,000 illuminations by the moon, I might compose and give a priori, that is construct, the degree of our sensations of the sun-light.* We may therefore entitle these two principles constitutive. |
| [*Footnote; Kant's meaning is; The two principles enunciated under the heads of "Axioms of Intuition," and "Anticipations of Perception," authorize the application to phenomena of determinations of size and number, that is of mathematic. |
| For exampkle, I may compute the light of the sun, and say that its quantity is a certain number of times greater than that of the moon. |
| In the same way, heat is measured by the comparison of its different effects on water, &c., and on mercury in a thermometer.--Tr] |
| The case is very different with those principles whose province it is to subject the existence of phenomena to rules a priorI. For as existence does not admit of being constructed, it is clear that they must only concern the relations of existence and be merely regulative principles. |
| In this case, therefore, neither axioms nor anticipations are to be thought of. |
| Thus, if a perception is given us, in a certain relation of time to other (although undetermined) perceptions, we cannot then say a priori, what and how great (in quantity) the other perception necessarily connected with the former is, but only how it is connected, quoad its existence, in this given modus of time. |
| Analogies in philosophy mean something very different from that which they represent in mathematics. |
| In the latter they are formulae, which enounce the equality of two relations of quantity, and are always constitutive, so that if two terms of the proportion are given, the third is also given, that is, can be constructed by the aid of these formulae. |
| But in philosophy, analogy is not the equality of two quantitative but of two qualitative relations. |
| In this case, from three given terms, I can give a priori and cognize the relation to a fourth member, but not this fourth term itself, although I certainly possess a rule to guide me in the search for this fourth term in experience, and a mark to assist me in discovering it. |
| An analogy of experience is therefore only a rule according to which unity of experience must arise out of perceptions in respect to objects (phenomena) not as a constitutive, but merely as a regulative principle. |
| The same holds good also of the postulates of empirical thought in general, which relate to the synthesis of mere intuition (which concerns the form of phenomena), the synthesis of perception (which concerns the matter of phenomena), and the synthesis of experience (which concerns the relation of these perceptions). |