And now a little about motives.  The animal begins with appetite, and some animals and men never get any farther.  And yet how easily this appetite for food is satiated!  We all remember our experiences as children around the Thanksgiving or Christmas table.  What a disappointment it was to us to find how soon our appetite had forsaken us, and that we had lost the power of enjoying the delicacies which we had most anticipated.  And over-indulgence often brought sad results and was followed by a period of penitential fasting.  And the appetites for sense gratification must always lead to this result.  They not only crave things which “perish with the using;” temporarily at least, often permanently, the appetite itself perishes with the gratification.

But what of the appetite, if you will pardon the expression, for truth and right?  All attainment only strengthens it; and, instead of enslaving, it makes men ever more free.  And yet what a power there is in the appetite for truth and righteousness?  In obedience to it man gives his body to be burned, or pours out his life-blood drop by drop for its attainment, and rejoices in the sacrifice.  There are victims to appetite:  there are only martyrs to truth.  This soul hunger for truth and right, growing more intense as the soul is filled with the object of desire, is the only one capable of indefinite development and dominance of the will.  This must be and is the mental goal of animal development, if man has a future corresponding in length at all to his past.  Otherwise the history of life becomes a “story told by an idiot.”  For its satisfaction is the only one which never causes satiety, and of which over-indulgence is impossible.  All others lead only to a slough of despond, or the deeper and more treacherous slough of contentment, beyond which rise no delectable mountains or golden city.

And now in closing let me call your attention to one thought of practical vital importance.

According to the theory which we have agreed to adopt, higher species have arisen through a process of natural selection, those species surviving which are best conformed to their environment.  And this applies to man as well as to lower animals.  All knowledge is in man, therefore, primarily, a means by which he may conform to environment, survive, and progress.  But conformity includes more than mere knowledge of environment.  A man might have all knowledge, and yet refuse to conform; and then his knowledge could not save him from destruction.  For conformity alone gives survival.  Conformity in man requires an effort of the will.  It is intelligent, but it is also voluntary action.  And knowledge is a necessary means of conformity because through it we see how we may conform, and because it furnishes the motives which stimulate the will to the necessary effort.