It would seem to be clear that there is a sequence of dominance in the faculties of the intellect.  First, the only means of acquiring knowledge is through sense-perception.  But memory dawns far down in the animal kingdom.  And thus the animal begins to associate past experience with present objects.  The bee remembers the gaining of honey in the past, associated with the color of the flower which she now sees, and knows that honey is to be attained again.  Thus in time association leads to inference, and understanding has dawned.  But the highest faculty of the intellect is the rational intelligence, which perceives beauty, truth, and goodness.  This is the last to develop.  Traces of its working may be perhaps discovered below man, but only in man does it become dominant.  Through it I perceive my rights and duties, and come to the consciousness of my own personality as a moral agent.  This tells me of the relation of my own personality to other persons and things.  And these are evidently the most important objects of human study.  The attainment of this knowledge and the development of this faculty are evidently the goal of human intellectual development.  This it is which has insured progress and raised man ever higher above the brutes.

Before we can proceed to the study of the will we must clearly recognize and define certain modes of mental and nervous action, which sooner or later manifest themselves in muscular activity.  For, while certain of our bodily activities are clearly voluntary, others take place wholly, or in part independently, of the individual will.  Between these different modes of bodily action we must distinguish as clearly as may be possible.

1.  Reflex Action.  I touch something cold or hot in the dark, suddenly and unexpectedly.  I draw back my hand involuntarily and before I have perceived the sensation of cold or heat.  You tell me to keep my eyes open while you make a sudden pass at them with your hand.  I try hard to do so, but my eyes shut for all that.  I shut them unconsciously and against my own will.  I say, “They shut of themselves.”  Now, this is not true, but the explanation is not difficult.  These and similar actions are entirely possible, although the continuity between spinal marrow and brain may have been so interrupted by some accident that sensation in the reflexly active part fails altogether.  A bird flaps its wings after its head is cut off, and yet the seat of consciousness and will is certainly in the brain.  A patient with a “broken back,” and paralyzed in his legs, will draw up his feet if they are tickled, although he is entirely unable to move them by any effort of his will and has no consciousness of the irritation.