Whenever we find any contrivances all combining to secure a certain good result, which, at the same time, involve some degree of inevitable evil, and then discover that there are contrivances to diminish and avoid this evil, we properly infer that the author intended to secure _as much of the good with as little of the evil as possible_. For example, a traveler finds a deserted mine, and all around he discovers contrivances for obtaining gold, and, at the same time, other contrivances for getting rid of the earth mixed with it. The inevitable inference would be that the author of these contrivances designed to secure as much gold with as little earth as possible; and should any one say that he could have had more gold and less earth if he chose to, the answer would be that there is no evidence of this assertion, but direct evidence against it.
Again: should we discover a piece of machinery in which every contrivance tended to secure a _speed_ in movement, produced by the _friction_ of wheels against a rough surface, and at the same time other contrivances were found for diminishing all friction that was useless, we should infer that the author designed to secure the _greatest possible speed_ with the _least possible friction_.
In like manner, if we can show that mind is a contrivance that acts by the influence of fear of evil, and that _pain_ seems as indispensable to the action of a free agent as friction is to motion; if we can show that there is no contrivance in mind or matter which is designed to secure suffering as its primary end; if we can, on the contrary, show that the direct end of all the organizations of mind and matter is to produce happiness; if we can show that it is only the _wrong action_ of mind that involves most of the pain yet known, so that right action, in its place, would secure only happiness; if we can show contrivances for diminishing pain, and also contrivances for increasing happiness by means of the inevitable pain involved in the system of things, then the just conclusion will be gained that the Author of the system of mind and matter designed "to produce the greatest possible happiness with the least possible evil."
In the pages which follow, we shall present evidence exhibiting all these particulars.