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."[3] In the review which follows, we shall present evidence exhibiting all these particulars. The only way in which we learn the nature of a thing is to observe its qualities and actions. This is true of mind as much as it is of matter. Experience and observation teach that the nature of mind is such that _the fear of suffering_ is indispensable to secure a large portion of the enjoyment within reach of its faculties, and that the highest modes of enjoyment can not be secured except by sacrifice, and thus by more or less suffering. This appears to be an inevitable combination, as much so as friction is inevitable in machinery. We have the evidence of our own consciousness that it is fear of evil to ourselves or to others that is the _strongest_ motive power to the mind. If we should find that no pain resulted from burning up our own bodies, or from drowning, or from any other cause; if every one perceived that no care, trouble, or pain resulted from losing all kinds of enjoyment, the effort to seek it would be greatly diminished. If we could desire good enough to exert ourselves to seek it, and yet should feel no discomfort in failing; if we could _lose every thing_, and feel no sense of pain or care, the stimulus to action which experience has shown to be most powerful and beneficent would be lost. We find that abundance of ease and prosperity enervates mental power, and that mind increases in all that is grand and noble, and also in the most elevating happiness, by means of danger, care, and pain. We may properly infer, then, that evil is a necessary part of the experience of a perfectly-acting mind. So strong is the conviction that _painful penalties_ are indispensable, that the kindest parents and the most benevolent rulers are the most sure to increase rather than diminish those that are already involved in the existing nature of things.