Finally, progress in medicine, the use of more wholesome food and healthy houses, the diminution of the two most active causes of deterioration, namely, misery and excessive wealth, must prolong the average duration of life, as well as raise the tone of health while it lasts. The force of transmissable diseases will be gradually weakened, until their quality of transmission vanishes. May we then not hope for the arrival of a time when death will cease to be anything but the effect either of extraordinary accidents, or of the destruction, ever slower and slower, of the vital forces? May we not believe that the duration of the middle interval between birth and this destruction has no assignable term? Man will never become immortal, but is it a mere chimera to hold that the term fixed to his years is slowly and perpetually receding further and further from the moment at which his existence begins?[81] * * * * * The rapidity and the necessary incompleteness with which Condorcet threw out in isolated hints his ideas of the future state of society, impart to his conception a certain mechanical aspect, which conveys an incorrect impression of his notion of the sources whence social change must flow. His admirable and most careful remarks upon the moral training of children prove him to have been as far removed as possible from any of those theories of the formation of character which merely prescribe the imposition of moulds and casts from without, instead of carefully tending the many spontaneous and sensitive processes of growth within.[82] Nobody has shown a finer appreciation of the delicacy of the material out of which character is to be made, and of the susceptibility of its elementary structure; nor of the fact that education consists in such a discipline of the primitive impulses as shall lead men to do right, not by the constraint of mechanical external sanctions, but by an instant, spontaneous, and almost inarticulate repugnance to cowardice, cruelty, apathy, self-indulgence, and the other great roots and centres of wrong-doing. It was to a society composed of men and women whose characters had been shaped on this principle, that Condorcet looked for the realisation of his exalted hopes for humanity.[83]