We have seen that there are only these sources of human knowledge, viz., the _intuitive truths_, _human experience_, _reasoning_, and _revelation_. We have alluded to the nature of intuitive knowledge; we will now inquire as to the nature of the knowledge gained by human experience, firstly, in regard to the _constitution of mind and the laws of that system in which it is placed_. We restrict our inquiries to those points which have the most direct bearing on the great questions to be discussed. As it respects the nature of mind, then, as exhibited by experience, we learn, in the first place, that it is constituted with desires and propensities for various kinds of enjoyment. These are the gratifications secured by the senses, the pleasures of taste, the happiness of giving and receiving affection, the various intellectual pleasures, and the still higher enjoyment resulting from our moral nature. All these are common to the race, though in varied degrees and combinations. The mind is also constituted with susceptibilities to pain and suffering from all the sources from which enjoyment may spring. With these susceptibilities are combined an all-pervading and constant _desire_ to gain enjoyment and to escape suffering. This desire is the grand _motive_ power to the mind, as the main-spring is to a watch. For this reason, awakened desires to gain any particular enjoyment or escape any pain are called _motives_. And so, also, all those things that cause these desires are called motives. Next, it is seen that the mind is endowed with intellect, or the intellectual powers, by which it can perceive the nature and relative value of various kinds of enjoyment, compare the present with the future, and judge both of what is most valuable and of the proper modes of securing it. To this add the power of choice or volition, by which, in view of any two or more kinds of enjoyment, the mind decides which shall be secured and which be denied. Thus constituted, the mind comes into action in a _system of law_. By this is signified that in every direction in which man can seek enjoyment there is a right course, or one that secures the good sought in such proper degrees and at such times as that the enjoyment designed is the result. At the same time there is a wrong course, or one in which the enjoyment sought is not secured, or, if gained, is combined with pain and disappointment. Thus there are right and wrong modes of seeking all the multiplied kinds of enjoyment, while to the right course is attached the reward of pleasure, and with the wrong course is connected the penalty of pain, either immediate or remote.