But Epicurus could only borrow the leading principle of his opponents at the expense of an enormous inconsistency. It was long ago pointed out by the Academicians—and the objection has never been answered—that pleasure and mere painlessness cannot both be the highest good, although the one may be an indispensable condition of the other. To confound the means with the end was, indeed, a common fault of Greek philosophy; and the Stoics also were guilty of it when they defined self-preservation to be the natural object of every creature, and yet attached a higher value to the instruments than to the aims of that activity. In Epicureanism, however, the change of front was more open, and was attempted under the eyes of acute and vigilant enemies. If the total absence of pain involves a pleasurable state of consciousness, we have a right to ask for a definition or description of it, and this, so far as can be made out, our philosopher never pretended to supply. Of course, a modern psychologist can point out that the functions of respiration, circulation, secretion, and absorption are constantly going on, and that, in their normal activity, they give rise to a vast sum of pleasurable consciousness, which far more than makes up in volume for what it wants in acuteness. But, whatever his recent interpreters may say,[133] Epicurus nowhere alludes to this diffused feeling of vitality; had he recognised it, his enumeration of the positive sensations, apart from which the good is inconceivable, would have seemed as incomplete to him as it does to us. If, on the other hand, the complete removal of pain introduces us to a state of consciousness, which, without being positively pleasurable, has a positive value of some kind, we ought to be told wherein it differs from the ideals of the spiritualist school; while, if it has no positive value at all, we ought equally to be told wherein it differs from the unconsciousness of sleep or of death. III.