| If, for example, I consider a leaden ball, which lies upon a cushion and makes a hollow in it, as a cause, then it is simultaneous with the effect. |
| But I distinguish the two through the relation of time of the dynamical connection of both. |
| For if I lay the ball upon the cushion, then the hollow follows upon the before smooth surface; but supposing the cushion has, from some cause or another, a hollow, there does not thereupon follow a leaden ball. |
| Thus, the law of succession of time is in all instances the only empirical criterion of effect in relation to the causality of the antecedent cause. |
| The glass is the cause of the rising of the water above its horizontal surface, although the two phenomena are contemporaneous. |
| For, as soon as I draw some water with the glass from a larger vessel, an effect follows thereupon, namely, the change of the horizontal state which the water had in the large vessel into a concave, which it assumes in the glass. |
| This conception of causality leads us to the conception of action; that of action, to the conception of force; and through it, to the conception of substance. |
| As I do not wish this critical essay, the sole purpose of which is to treat of the sources of our synthetical cognition a priori, to be crowded with analyses which merely explain, but do not enlarge the sphere of our conceptions, I reserve the detailed explanation of the above conceptions for a future system of pure reason. |
| Such an analysis, indeed, executed with great particularity, may already be found in well-known works on this subject. |
| But I cannot at present refrain from making a few remarks on the empirical criterion of a substance, in so far as it seems to be more evident and more easily recognized through the conception of action than through that of the permanence of a phenomenon. |
| Where action (consequently activity and force) exists, substance also must exist, and in it alone must be sought the seat of that fruitful source of phenomena. |
| Very well. |
| But if we are called upon to explain what we mean by substance, and wish to avoid the vice of reasoning in a circle, the answer is by no means so easy. |
| How shall we conclude immediately from the action to the permanence of that which acts, this being nevertheless an essential and peculiar criterion of substance (phenomenon)? |
| But after what has been said above, the solution of this question becomes easy enough, although by the common mode of procedure--merely analysing our conceptions--it would be quite impossible. |
| The conception of action indicates the relation of the subject of causality to the effect. |
| Now because all effect consists in that which happens, therefore in the changeable, the last subject thereof is the permanent, as the substratum of all that changes, that is, substance. |
| For according to the principle of causality, actions are always the first ground of all change in phenomena and, consequently, cannot be a property of a subject which itself changes, because if this were the case, other actions and another subject would be necessary to determine this change. |
| From all this it results that action alone, as an empirical criterion, is a sufficient proof of the presence of substantiality, without any necessity on my part of endeavouring to discover the permanence of substance by a comparison. |
| Besides, by this mode of induction we could not attain to the completeness which the magnitude and strict universality of the conception requires. |
| For that the primary subject of the causality of all arising and passing away, all origin and extinction, cannot itself (in the sphere of phenomena) arise and pass away, is a sound and safe conclusion, a conclusion which leads us to the conception of empirical necessity and permanence in existence, and consequently to the conception of a substance as phenomenon. |