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°, of affinity to oxygen ; 2°, of contact with oxygen ; 3°, 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
