This test of identity, as I have said in my Essay on the subject, appears to me to be a most accurate one. When a proposition is true, and yet communicates no additional information, it must be of exactly the same import, as some other proposition, formerly understood and admitted. Let us suppose ourselves, then, to know all the antecedents and consequents in nature, and to believe, not merely that they have once or repeatedly existed in succession, but that they have uniformly done so, and will continue forever to recur in similar series, so that, but for the intervention of the Divine will, which would be itself, in that case, a new antecedent, it will be absolutely impossible for any one of the antecedents to exist again, in similar circumstances, without being instantly followed by its original consequent. If an effect be something more than what invariably follows a particular antecedent, we might, on the present supposition, know every invariable consequent of every antecedent, so as to be able to predict, in their minutest circumstance, what events would forever follow every other event, and yet have no conception of power or causation. We might know, that the flame of a candle, if we hold our hand over it, would be instantly followed by pain and burning of the hand,--that, if we ate or drank a certain quantity, our hunger and thirst would cease:--we might even build houses for shelter, sow and plant for sustenance, form legislative enactments for the prevention or punishment of vice, and bestow rewards for the encouragement of virtue;--in short, we might do, as individuals and citizens, whatever we do at this moment, and with exactly the same views, and yet, (on the supposition that power is something different from that invariable antecedence which alone we are supposed to know,) we might with all this unerring knowledge of the future, and undoubting confidence in the results which it was to present, have no knowledge of a single power in nature, or of a single cause or effect. To him who had previously kindled a fire, and placed on it a vessel full of water, with the certainty that the water, in that situation, would speedily become hot, what additional information would be given, by telling him that the fire had the _power_ of boiling water, that it was the _cause_ of the boiling, and the boiling its _effect_? And, if no additional information would in this case be given, then, according to the test of this identity of propositions, before stated, to know events as invariably antecedent and consequent, is to know them as causes and effects; and to know all the powers of every substance therefore, would be only to know what changes or events would, in all possible circumstances, ensue, when preceded by certain other changes or events. It is only by confounding _casual_ with uniform and invariable antecedence, that power can be conceived, to be something different from antecedence. It certainly is something very