In this passage the man himself is speaking, and disclosing his innermost convictions. For Abaelard’s nature was set upon understanding all things through reason, even the mysteries of the Faith. He does not say, or quite think, that he will disbelieve whatever he cannot understand; but his reasoning and temper point to the conclusion. This was obviously true of Abaelard’s ethical opinions; his enemies said it was true of his theology. Such a man would naturally plead for freedom of discussion, even for freedom of conclusion; but within certain bounds; for who in the twelfth century could maintain that heretics or infidels did rightly in rejecting the Christian Faith? Yet Abaelard says heretics should be compelled (_coercendi_) by reason rather than force.[469] And he could at least conceive of the rejection of the Faith upon, say, imperfect rational grounds. In his dialogue between Philosopher, Jew, and Christian, the Christian says to the Philosopher: One cannot argue against you from the authority of Scripture, which you do not recognize; for no one can be refuted save with arguments drawn from what he admits: _Nemo quippe argui nisi ex concessis potest_.[470] However this sounded in Abaelard’s time, the same was enunciated by Thomas Aquinas after him, in a passage already given.[471] But it is doubtful whether Thomas would have cared to follow Abaelard in some of the arguments of his _Ethics_ or _Book called, Know Thyself_, in which he maintains that no act is a sin unless the actor was conscious of its sinfulness; and therefore that killing the martyrs could not be imputed as sin to those persecutors who deemed themselves thereby to be doing a service acceptable to God.[472] The titles given by Abaelard to his various treatises are indicative of the critical insistency of his nature. He called his _Ethica_, _Scito te ipsum_, _Know Thyself_: understand thy good and ill intentions, and what may be vice or virtue in thee. Through the book, the discussion of right and wrong directs itself as pertinaciously to considerations of human nature as was possible in an age when theological dogma held the final criteria of human conduct. And Abaelard is capable of a lofty insight touching the relationship between God and man. “Penitence,” says he, “is truly fruitful when grief and contrition proceed from love of God, regarded as benignant, rather than from fear of penalties. Sin cannot endure with this groaning and contrition of heart: for sin is contempt of God, or consent to evil, and the love of God in inspiring our groaning, suffers no ill.”[473]