He was conscious of a mind of singular acuteness and a tongue of parts, both of which would do whatever he willed.

Beneath all the tumultuous talk of Paris, when he first arrived there, lay the great and unsolved problem of Universals and this he promptly made his own, rushing in where others feared to tread.

William of Champeaux had rested on a Platonic basis, Abelard assumed that of Aristotle, and the clash began.

It is not a lucid subject, but the best abstract may be found in Chapter XIV of Henry Adams' "Mont-Saint-Michel and Chartres" while this and the two succeeding chapters give the most luminous and vivacious account of the principles at issue in this most vital of intellectual feuds.
"According to the latest authorities, the doctrine of universals which convulsed the schools of the twelfth century has never received an adequate answer.

What is a species: what is a genus or a family or an order?
More or less convenient terms of classification, about which the twelfth century cared very little, while it cared deeply about the essence of classes! Science has become too complex to affirm the existence of universal truths, but it strives for nothing else, and disputes the problem, within its own limits, almost as earnestly as in the twelfth century, when the whole field of human and superhuman activity was shut between these barriers of substance, universals, and particulars.