| From all this it is evident that, in the first place, I cannot reverse the order of succession, and make that which happens precede that upon which it follows; and that, in the second place, if the antecedent state be posited, a certain determinate event inevitably and necessarily follows. |
| Hence it follows that there exists a certain order in our representations, whereby the present gives a sure indication of some previously existing state, as a correlate, though still undetermined, of the existing event which is given--a correlate which itself relates to the event as its consequence, conditions it, and connects it necessarily with itself in the series of time. |
| If then it be admitted as a necessary law of sensibility, and consequently a formal condition of all perception, that the preceding necessarily determines the succeeding time (inasmuch as I cannot arrive at the succeeding except through the preceding), it must likewise be an indispensable law of empirical representation of the series of time that the phenomena of the past determine all phenomena in the succeeding time, and that the latter, as events, cannot take place, except in so far as the former determine their existence in time, that is to say, establish it according to a rule. |
| For it is of course only in phenomena that we can empirically cognize this continuity in the connection of times. |
| For all experience and for the possibility of experience, understanding is indispensable, and the first step which it takes in this sphere is not to render the representation of objects clear, but to render the representation of an object in general, possible. |
| It does this by applying the order of time to phenomena, and their existence. |
| In other words, it assigns to each phenomenon, as a consequence, a place in relation to preceding phenomena, determined a priori in time, without which it could not harmonize with time itself, which determines a place a priori to all its parts. |
| This determination of place cannot be derived from the relation of phenomena to absolute time (for it is not an object of perception); but, on the contrary, phenomena must reciprocally determine the places in time of one another, and render these necessary in the order of time. |
| In other words, whatever follows or happens, must follow in conformity with a universal rule upon that which was contained in the foregoing state. |
| Hence arises a series of phenomena, which, by means of the understanding, produces and renders necessary exactly the same order and continuous connection in the series of our possible perceptions, as is found a priori in the form of internal intuition (time), in which all our perceptions must have place. |
| That something happens, then, is a perception which belongs to a possible experience, which becomes real only because I look upon the phenomenon as determined in regard to its place in time, consequently as an object, which can always be found by means of a rule in the connected series of my perceptions. |
| But this rule of the determination of a thing according to succession in time is as follows; "In what precedes may be found the condition, under which an event always (that is, necessarily) follows." From all this it is obvious that the principle of cause and effect is the principle of possible experience, that is, of objective cognition of phenomena, in regard to their relations in the succession of time. |
| The proof of this fundamental proposition rests entirely on the following momenta of argument. |
| To all empirical cognition belongs the synthesis of the manifold by the imagination, a synthesis which is always successive, that is, in which the representations therein always follow one another. |
| But the order of succession in imagination is not determined, and the series of successive representations may be taken retrogressively as well as progressively. |
| But if this synthesis is a synthesis of apprehension (of the manifold of a given phenomenon), then the order is determined in the object, or to speak more accurately, there is therein an order of successive synthesis which determines an object, and according to which something necessarily precedes, and when this is posited, something else necessarily follows. |
| If, then, my perception is to contain the cognition of an event, that is, of something which really happens, it must be an empirical judgement, wherein we think that the succession is determined; that is, it presupposes another phenomenon, upon which this event follows necessarily, or in conformity with a rule. |
| If, on the contrary, when I posited the antecedent, the event did not necessarily follow, I should be obliged to consider it merely as a subjective play of my imagination, and if in this I represented to myself anything as objective, I must look upon it as a mere dream. |
| Thus, the relation of phenomena (as possible perceptions), according to which that which happens is, as to its existence, necessarily determined in time by something which antecedes, in conformity with a rule--in other words, the relation of cause and effect--is the condition of the objective validity of our empirical judgements in regard to the sequence of perceptions, consequently of their empirical truth, and therefore of experience. |
| The principle of the relation of causality in the succession of phenomena is therefore valid for all objects of experience, because it is itself the ground of the possibility of experience. |
| Here, however, a difficulty arises, which must be resolved. |