Though the mental processes of an individual preserve a working harmony, some of them appear more rational than others. Such disparities may be glaring in men who enter upon the learning of a higher civilization without proper pilotage. How are they to discriminate between the valuable and the foolish? The common sense, which they apply to familiar matters, contrasts with their childlike lucubrations upon novel topics of education or philosophy. And if that higher culture to which such pupils are introduced be in part decadent, it will itself contain disparities between the stronger thinking held in the surviving writings of a prior time and the later degeneracies which are declining to the level, it may be, of these new learners. There would naturally be disparities in the mental processes of an Anglo-Saxon like Alcuin introduced to the debris of Latin education and the writings of the Fathers; and his state would typify the character of the studies at the palace school of Charlemagne and at monastic schools through his northern realm. This newly stimulated scholarship held the same disparities that appear in the writings of Alcuin. He may seem to be adapting his teaching to barbaric needs, but it is evident that his matter accords with his own intellectual tastes, as, for example, when he introduces into his educational writings the habit of riddling in metaphors, so dear to the Anglo-Saxon.[250] The sound but very elementary portions of his teaching were needed by the ignorance of his scholars. For instance, no information regarding Latin orthography could come amiss in the eighth century. And Alcuin in his treatise on that subject[251] took many words commonly misspelled and contrasted them with those which sounded like them, but were quite different in meaning and derivation. One should not, for example, confuse _habeo_ with _abeo_; or _bibo_ and _vivo_. Such warnings were valuable. The use of the vulgar Romance-forms of Latin spoken through a large part of Charles’s dominions implied no knowledge of correct Latinity. Even among the clergy, there was almost universal ignorance of Latin orthography and grammar.