328 MEMOIR OF AUGUSTUS DE MORGAN. 



1864. I often cut from a review and paste haphazard on to the fly- 



leaf of a book. In your Plato articles I find, in this way, a 

 curious accidental paraphrase of the Trinity that may amuse 

 you. The Druse system is described as historically identified 

 with the Caliph Hakem, the Persian Hamze, and the Turk 

 Davagi Hakem the ' political founder J Hamze the * intellectual 

 (Xoyos) framer,' and Davagi the ' expositor and propagator.' 

 (Athenceum, August 27, 1853.) I am, dear sir, 



Yours truly, 



A. DE MORGAN. 



To J. S. Mill, Esq. 



91 Adelaide Road, February 5, 1865. 



1865. MY DEAR SIR, The Algebra, which I am much pleased to 



find you approve of, is to be divided between several. I have 

 no doubt I may claim to have first presented it complete, and 

 the connection, of A * with the rest is my own. But Warren, 

 Peacock, and others of those mentioned in my list at the 

 beginning of the work are real predecessors. You are perhaps 

 aware that Peacock published two works on algebra. The first, 

 in one volume, is that which treats the subject most generally. 

 He is in full possession of all except what relates to the ex- 

 ponent, and here he is obliged to have recourse to interpretation, 

 that is, discovery of meaning from results. 



With regard to the acceptance of the system, the time is not 

 yet come. The algebraists almost all make algebra obey their 

 preconceived notions. They have laws which algebra must obey. 

 Peacock had very nearly attained the idea of algebra as a, formal 

 science, in which every result of the form is to have meaning. 

 His permanence of equivalent forms would have developed itself 

 into formal algebra capable of any number of material applica- 

 tions, if he had been a logician I mean a student of logic. So 

 long as an algebraist has preconceptions which his science must 

 obey, so long is he incapable of true generalisation. Macaulay 

 said of Southey that what he called his opinions were his tastes, 

 and this is true of many persons, and of a great many algebraists. 

 Algebra must, a priori, be subject to this or that limitation, upon 

 what is really an acquired taste of the legislator. Pure logic is 

 in the same predicament. 



1 I am not sure about this exponent. ED. 



