Why is almost every thing forgotten that passed during our infancy? Why have old men a more distinct remembrance of what happened in their prime of life than what occurred in their more advanced years? Can there be a stronger proof that sensations alone are not sufficient to produce memory, and that it exists solely in the train of ideas which our minds derive from those sensations? In infancy the sensations are as lively and rapid as in manhood, yet they leave few or no traces, because at this era the power of reflection, which alone can form ideas is almost totally inactive; and because in the moments it does act, its comparisons are only superficial. In manhood reason is completely developed, because the power of reflection is in full exercise; we then derive from our sensations every possible advantage, and form many orders of ideas, and chains of thought, whereof each, from being often revolved, forms so durable and indelible an impression, that when old age comes on, those very ideas present themselves with more force than those derived from present sensations, because at that period the sensations are feeble, slow and dull, and the mind itself partakes of the languor of the body. In infancy, the time present is every thing; in manhood, we equally enjoy the past, the present and the future; in old age we have little sense of the present, we turn our eyes to the future, and exist in the past. In the infant that prattles, and the old man that dotes, reason is alike imperfect, because they are alike void of ideas; the former is as yet unable to form them, and the latter has ceased. An idiot, whose corporeal senses and organs appear to be sound, has, like us, sensations of all kinds; he will also have them in the same order, if he lives in society, and is obliged to act as other men. As these sensations do not create in him ideas, as there is no correspondence between his mind and his body, and as he is incapable of reflection, so he is necessarily destitute of memory, and all knowledge of himself. In nothing does such a man differ from a brute, as to the exterior faculties, for though he has a soul, and possesses the principle of reason, yet as this principle remains in a state of inaction, and receives nothing from the corporeal organs, it can have no influence upon his actions which are like those of an animal, solely determined by its sensations, and by a sentiment of its existence and present wants. Thus the idiot and the brute are beings whose operations are in every respect the same, because the one has no soul, and the other makes not any use of it; they are both destitute of the power of reflection, and of course have neither understanding nor memory.