THE DEVELOPMENT OF PSYCHOLOGY. 291 



without which Aquinas's own unquestionable advance upon Averroes 

 might never, or not so soon, have been made. While, however, Thomas 

 successfully asserted against the Arabians the individuality of the soul,^ 

 and against the older Aristotelians its substantial unity,^ there was 

 still another step to be taken before its independence on all sides could 

 be regarded as established, and the ground cleared for the science of 

 Psychology. That step was taken by Descartes, in whom mankind 

 may be said to have come to a consciousness of itself. His " Cogito, 

 ergo sum " (I think ; therefore I am), was not logical, but genetic. 

 The force of the ergo (therefore), as Ferrier long ago pointed out, lay 

 in the fact that the existence of Descartes as a self-conscious being — 

 sum (I am) — was resultant upon the process described by the word 

 cogito (I think) — the turning of the light of self-consciousness upon 

 the thinking principle itself. We have but extended Ferrier's inter- 

 pretation from the development of self-consciousness in the individual 

 to the metaphysical evolution of the ego (me) in human history. Xot 

 till this had been accomplished, and tlie Mind made a separate indi- 

 vidual existence as against God and l^ature, was any independent 

 science of Psychology possible. Observations and reasonings on 

 Man, as on the Deity and the Creation, formed part of the " undiffer- 

 entiated" mass of speculation on things in general called Cosmology 

 or Theology, and latterly, in a mutilated condition, Metaphysics. Any 

 mediaeval cyclopaedia will furnish illustrations. 



Thomas Aquinas, a faithful representative of the frightened ortho- 

 doxy of the Middle Ages, unsuspectingly follows the course of Crea- 

 tion, well known to have happened as laid down in the Book of Gen- 

 esis*. After forty-four QucBstiones (Questions) on God (under whom 

 he discusses the nature of ideas and the metaphysics of truth) and 

 the Trinity, and thirty on the Angels, the Devils (here arises, naturally, 

 a discussion on the nature of evil), and the seven days of creation and 

 rest, Thomas arrives, by an obvious logical sequence, at the psychology 

 of man. One qucestio (question) settles the essence of the soul, another 

 the union of soul and body; three exhaust the powers of mind in 

 general and special, and the intellectual powers ; four expound appe- 

 tite, sensuality, the will, and free-will ; and, having in seven more dis- 

 posed of the remaining faculties of the soul, including such small 

 subjects as "the mode and order of intellection," Thomas is prepared 

 to deal with the production of man's body, and then evidently with 

 the production of woman's body.^ A witty journalist is reported 

 to have said of an eminent living thinker, " God made the world 

 in six days, and So-and-so wrote it down on the seventh ; " but 

 the entire Synthetic Philosophy might fall out of a corner of the 



^ " Quaestiones Disputata3." De Spiritualibus Creaturis, artt. ix.-x., and De Anima, 

 artt. ii., iii., v. 



2 Bain, " Mind and Body," p. 181. 



2 '* Summa Theologiae," prima pars, qu. ii.-xcii. 



