The foremost outstanding is perhaps "the unity of the world." Confronted by the perplexing menace of the variation of experience, the dichotomies and oppositions of thoughts and things, the fusion and diversifications of many things into one and one into many, mankind has, from the moment it became reflective, felt in the relation of the One and the Many the presence of a riddle that engendered and sustained uneasiness, a mystery that concealed a threat. The mind's own preference, given the physiological processes that condition its existence, constitution, and operation, could hardly come to rest in a more fundamental normation than Unity. A world which is _one_ is easier to live in and with; initial adjustment therein is final adjustment; in its substance there exists nothing sudden and in its character nothing uncontrollable. It guarantees whatever vital equilibrium the organism has achieved in it, ill or good. It secures life in attainment and possession, insuring it repose, simplicity, and spaciousness. A world which is many complicates existence: it demands watchful consideration of irreducible discrete individualities: it necessitates the integration and humanization in a common system of adjustment of entities which in the last analysis refuse all ordering and reject all subordination, consequently keeping the mind on an everlasting jump, compelling it to pay with eternal vigilance the price of being. The preference for unity, then, is almost inevitable, and the history of philosophy, from the Vedas to the Brahma Somaj and from Thales to Bergson, is significantly unanimous in its attempts to prove that the world is, somehow, through and through one. That the oneness requires _proof_ is _prima facie_ evidence that it is a value, a desiderate, not an existence. And how valuable it is may be seen merely in the fact that it derealizes the inner conflict of interests, the incompatibilities between nature and man, the uncertainties of knowledge, and the certainties of evil, and substitutes therefore the ultimate happy unison which "the identity of the different" compels.