The chief source of all this passion is that thought for what is absent and future, which, with man, exercises such a powerful influence upon all he does. It is this that is the real origin of his cares, his hopes, his fears—emotions which affect him much more deeply than could ever be the case with those present joys and sufferings to which the brute is confined. In his powers of reflection, memory and foresight, man possesses, as it were, a machine for condensing and storing up his pleasures and his sorrows. But the brute has nothing of the kind; whenever it is in pain, it is as though it were suffering for the first time, even though the same thing should have previously happened to it times out of number. It has no power of summing up its feelings. Hence its careless and placid temper: how much it is to be envied! But in man reflection comes in, with all the emotions to which it gives rise; and taking up the same elements of pleasure and pain which are common to him and the brute, it develops his susceptibility to happiness and misery to such a degree that, at one moment the man is brought in an instant to a state of delight that may even prove fatal, at another to the depths of despair and suicide.