Every human faculty has some pleasure corresponding to it. The pleasure of the appetitive faculty for example, is to receive a sensation which accords with its desire; the pleasure of the irascible faculty is attack; the pleasure of the surmising faculty, hope; that of the recollective faculty, memory. Generally speaking, the pleasures attending these faculties consist in their realising themselves in action, but they differ widely in rank, the soul's delight in intellectual perception of realities, in which the knower and the known are one, being incomparably higher than any mere sensual satisfaction. By attaining to such perceptions, the soul prepares itself for the beatitude of the next life. The degree of this beatitude will correspond to the intensity of spiritual desire awakened in it during its earthly sojourn.[41] It is extremely difficult, not to say impossible, to determine the degrees of beatitude of the soul after death. We may, nevertheless, understand that the various impediments of passions, prejudices, etc., to which its union with the body has given rise, are not immediately dissolved on its separation from the body. Souls thus hindered may pass into a state depicted by Plato and other ancient philosophers, in which they are still weighed down by the passions they indulged in. Every soul is eternal and imperishable, and will finally attain the beatitude for which it was created. But it may be punished after death by a shorter or longer exclusion from that beatitude. To suppose with Alexander Aphrodisius that an imperfect or ill-prepared soul may be annihilated, would be to admit a belief at complete variance with its eternal essence and origin. But we may well conjecture that the punishment of such ill-prepared and refractory souls would consist in their being in a state in which after separation from the body they still pine after sensual enjoyments and suffer from the impossibility of such gratification. It may also be supposed that such ill-prepared souls remember the notions that were current in this world regarding beatitude and damnation; their conceptions would in that case resemble dreams which are often more vivid than impressions received in waking moments. They would imagine themselves undergoing the examination in the tomb and all the other punishments depicted in the Koran, or it may be enjoying the sensual pleasures there described. On the other hand, the noble and well-prepared soul will pass at once to the contemplation of the eternal, and will be exempt from every memory and every conception relating to this world. For if anything of this kind remained in it as a reminder of its union with the body, it would so far fall short of the plenitude of its perfection. Besides his mystical treatise "On the soul," Avicenna has left a short but remarkable poem on the same subject, which runs as follows:-- "THE SOUL.