The first condition of counting, then, is that the sensorium should retain something of the first impression while it receives the second, or (to state the corresponding mental fact) that the second sensation should be felt together with a survival of the first from which it is distinguished in point of existence and with which it is identified in point of character.
Now, to secure this, it is not enough that the sensorium should be materially continuous, or that a “spiritual substance” or a “transcendental ego” should persist in time to receive the second sensation after having received and registered the first. A perfectly elastic sensorium, a wholly unchanging soul, or a quite absolute ego might remain perfectly identical with itself through various experiences without collating them. It would then remain, in fact, more truly and literally identical than if it were modified somewhat by those successive shocks. Yet a sensorium or a spirit thus unchanged would be incapable of memory, unfit to connect a past perception with one present or to become aware of their relation. It is not identity in the substance impressed, but growing complication in the phenomenon presented, that makes possible a sense of diversity and relation between things. The identity of substance or spirit, if it were absolute, would indeed prevent comparison, because it would exclude modifications, and it is the survival of past modifications within the pres-