30 The Descent of Man 



aggregations, according to the laws of the association of 

 sensible perceptions. — Association. 



The above four groups contain only indeliberate operations, 

 consisting, as they do at the best, but of mere presentative 

 sensible ideas in no way implying any reflective or representa- 

 tive faculty. Such actions minister to and form Instinct 

 Besides these, we may distinguish two other kinds of mental 

 action, namely : — 



V. That in which sensations and sensible perceptions are 

 reflected on by thought, and recognised as our own, and we 

 ourselves recognised by ourselves as affected and perceiving. 

 — Self-consciousness. 



VI. That in which we reflect upon our sensations or per- 

 ceptions, and ask what they are and why they are. — Reason. 



These two latter kinds of action are deliberate operations, 

 performed as they are by means of representative ideas 

 implying the use of a reflective representative faculty. Such 

 actions distinguish the intellect or rational faculty. Now, we 

 assert that the full possession of all the first four (presenta- 

 tive) kinds of action, by no means implies the possession 

 of the last two (representative) kinds also. All persons, we 

 think, must admit the truth of the following propositions : — 



Two faculties are distinct, not in degree but in kind, if we 

 may possess the one in perfection without that fact implying 

 that we possess the other also. Still more Avill this be the 

 case if the two faculties tend to increase in an inverse ratio. 

 Yet this is the distinction between the instinctive and the 

 intellectual parts of man's nature. 



As to animals, we fully admit that they may possess all 

 the first four groups of actions — that they may have, so to 

 speak, mental images of sensible objects combined in all 

 degrees of complexity, as governed by the laws of association. 

 We deny to them, on the other hand, the possession of the 

 last two kinds of mental action. We deny to them, that is, 



