perpetuity of natural species(259) has been lately
assailed may enable us to realize the earnestness shown on this point in
the middle ages. The question, as viewed by the schoolmen, was really the
fundamental one as respects knowledge; and the opinions on it are the
counterpart to those which relate to the tests of truth and the nature of
being in modern metaphysics. The spirit of realism was essentially the
spirit of dogmatism, the disposition to pronounce that truth was already
known.(260) Nominalism was essentially the spirit of progress, of inquiry,
of criticism. Realism was in spirit deductive, starting from accepted
dogmas: Nominalism was in spirit, though not in form, inductive. It tested
classifications, and admitted opportunities for the existence of doubt.
"Believe that you may know," was the expression of the former: "Know that
you may believe," that of the latter.(261)

The two theories were of universal application to every subject of
thought. An illustration will explain their relation to theology. In the
foolish and almost irreverent attempts to explain by philosophy the nature
of the triune existence of the divine Being, the realist assuming the
reality of the one genus Deity, was prepared to allow identity of essence
in the three species, the three members of the Divine Trinity. The
nominalist, allowing only concrete existence, was obliged either to accept
unity, only in a verbal sense, and be charged with tritheism, as Roscelin;
or diversity only in a verbal sense, and incur the charge of Sabellianism,
as Abelard.

Such was Scholasticism, and such its relation to philosophy and
theology.(262) Existing for several centuries as an instinct, it became
about the end of the eleventh century an intelligent movement.(263) At
this period the problem was consciously proposed, and each of the three
centuries which are comprised in our present period exhibits a different
phase of the controversy. At first the movement was in favour of the
nominalism in Roscelin and Abelard, and reason assumed an attitude of
alleged scepticism: in the thirteenth century the victory was in the hands
of intelligent realists like Aquinas, who used reason in favour of
orthodoxy. In the fourteenth, nominalism revived in Occam; the provinces
of faith and philosophy were severed, and the final victory on the
metaphysical question remained in the hands of the nominalists.

The scientific position of Abelard will thus be clear. We must