The instinct of knowing and the instinct of living, or rather of surviving, come into conflict.  In his work on the Analysis of the Sensations and the Relation of the Physical to the Psychical,[32] Dr. E. Mach tells us that not even the investigator, the savant, der Forscher, is exempted from taking his part in the struggle for existence, that even the roads of science lead mouth-wards, and that in the actual conditions of the society in which we live the pure instinct of knowing, der reine Erkenntnisstrieb, is still no more than an ideal.  And so it always will be. Primum vivere, deinde philosophari, or perhaps better, primum supervivere or superesse.

Every position of permanent agreement or harmony between reason and life, between philosophy and religion, becomes impossible.  And the tragic history of human thought is simply the history of a struggle between reason and life—­reason bent on rationalizing life and forcing it to submit to the inevitable, to mortality; life bent on vitalizing reason and forcing it to serve as a support for its own vital desires.  And this is the history of philosophy, inseparable from the history of religion.

Our sense of the world of objective reality is necessarily subjective, human, anthropomorphic.  And vitalism will always rise up against rationalism; reason will always find itself confronted by will.  Hence the rhythm of the history of philosophy and the alternation of periods in which life imposes itself, giving birth to spiritual forms, with those in which reason imposes itself, giving birth to materialist forms, although both of these classes of forms of belief may be disguised by other names.  Neither reason nor life ever acknowledges itself vanquished.  But we will return to this in the next chapter.

The vital consequence of rationalism would be suicide.  Kierkegaard puts it very well:  “The consequence for existence[33] of pure thought is suicide....  We do not praise suicide but passion.  The thinker, on the contrary, is a curious animal—­for a few spells during the day he is very intelligent, but, for the rest, he has nothing in common with man” (Afsluttende uvidenskabelig Efterskrift, chap iii., Sec. 1).

As the thinker, in spite of all, does not cease to be a man, he employs reason in the interests of life, whether he knows it or not.  Life cheats reason and reason cheats life.  Scholastic-Aristotelian philosophy fabricated in the interest of life a teleologic-evolutionist system, rational in appearance, which might serve as a support for our vital longing.  This philosophy, the basis of the orthodox Christian supernaturalism, whether Catholic or Protestant, was, in its essence, merely a trick on the part of life to force reason to lend it its support.  But reason supported it with such pressure that it ended by pulverizing it.

I have read that the ex-Carmelite, Hyacinthe Loyson, declared that he could present himself before God with tranquillity, for he was at peace with his conscience and with his reason.  With what conscience?  If with his religious conscience, then I do not understand.  For it is a truth that no man can serve two masters, and least of all when, though they may sign truces and armistices and compromises, these two are enemies because of their conflicting interests.