In the Class of Objects for the Subject just described, the principle of sufficient reason figures as the _Law of Causality_, and, as such, I call it the _Principle of Sufficient Reason of Becoming, principium rationis sufficientis fiendi_. By it, all objects presenting themselves within the entire range of our representation are linked together, as far as the appearance and disappearance of their states is concerned, _i.e._ in the movement of the current of Time, to form the complex of empirical reality. The law of causality is as follows. When one or several real objects pass into any new state, some other state must have preceded this one, upon which the new state regularly follows, _i.e._ as often as that preceding one occurs. This sort of following we call _resulting_; the first of the states being named a _cause_, the second an _effect_. When a substance takes fire, for instance, this state of ignition must have been preceded by a state, 1^o, of affinity to oxygen; 2^o, of contact with oxygen; 3^o, of a given temperature. Now, as ignition must necessarily follow immediately upon this state, and as it has only just taken place, that state cannot always have been there, but must, on the contrary, have only just supervened. This supervening is called a _change_. It is on this account that the law of causality stands in exclusive relation to _changes_ and has to do with them alone. Every effect, at the time it takes place, is a _change_ and, precisely by not having occurred sooner, infallibly indicates some other _change_ by which it has been preceded. That other _change_ takes the name of _cause_, when referred to the following one--of _effect_, when referred to a third necessarily preceding _change_. This is the chain of causality. It is necessarily without a beginning. By it, each supervening state must have resulted from a preceding change: in the case just mentioned, for instance, from the substance being brought into contact with free heat, from which necessarily resulted the heightened temperature; this contact again depended upon a preceding change, for instance the sun's rays falling upon a burning-glass; this again upon the removal of a cloud from before the sun; this upon the wind; the wind upon the unequal density of the atmosphere; this upon other conditions, and so forth _in infinitum_. When a state contains all the requisite conditions for bringing about a new state excepting _one, this one_, when at last it arrives, is, in a sense, rightly called the cause κατ' ἐξοχήν, inasmuch as we here have the final--in this case the decisive--change especially in view; but if we leave out this consideration, no single condition of the causal state has any advantage over the rest with reference to the determination of the causal connection in general, merely because it happens to be the last. Thus the removal of the cloud in the above example, is in so far the cause of the igniting, as it took place later