He criticises the work of Duehring from this standpoint. He labors not so much to show that Duehring is mistaken in certain conclusions as to prove that the whole method of his argument is wrong. His diatribes, though the subject matter of his argument requires him to attack the Berlin tutor, are directed chiefly against all absolute theories. "Eternal truth," in the realm of science, equally with that of philosophy, he scouts as absurd. To interpret the history of the time in terms of the spirit of the time, to discover the actual beneath the crust of the conventional, to analyse the content of the formulae which the majority are always ready to take on trust, and to face the fact with a mind clear of preconceived notions is what Engels set out to do. It cannot be said that he altogether succeeded. No man can succeed in such a task. The prejudices and animosities created by incessant controversy warped his judgment in some respects, and tended on more than one occasion to destroy his love of fair play. The spirit which is occasionally shown in his controversial writing is to be deplored but it may be said in extenuation that all controversies of that time were disfigured in the same way. He pays the penalty for the fault. Much of the work is valueless to-day because of Engels' eagerness to score a point off his adversary rather than to state his own case. But where the philosopher lays the controversialist on one side for a brief period, and takes the trouble to elucidate his own ideas we discover what has been lost by these defects of temperament. He possesses in a marked degree the gift of clear analysis and of keen and subtle statement.