It is true as we have seen that, wherever complete demonstration of the nature of things would be too tedious, criticism must support itself on those truths which theory has established on the point. But, just as in War the actor obeys these theoretical truths rather because his mind is imbued with them than because he regards them as objective inflexible laws, so criticism must also make use of them, not as an external law or an algebraic formula, of which fresh proof is not required each time they are applied, but it must always throw a light on this proof itself, leaving only to theory the more minute and circumstantial proof. Thus it avoids a mysterious, unintelligible phraseology, and makes its progress in plain language, that is, with a clear and always visible chain of ideas.
Certainly this cannot always be completely attained, but it must always be the aim in critical expositions. Such expositions must use complicated forms of science as sparingly as possible, and never resort to the construction of scientific aids as of a truth apparatus of its own, but always be guided by the natural and unbiassed impressions of the mind.
But this pious endeavour, if we may use the expression, has unfortunately seldom hitherto presided over critical examinations: the most of them have rather been emanations of a species of vanity—a wish to make a display of ideas.
The first evil which we constantly stumble upon is a lame, totally inadmissible application of certain one-sided systems as of a formal code of laws. But it is never difficult to show the one-sidedness of such systems, and this only requires to be done once to throw discredit for ever on critical judgments which are based on them. We have here to deal with a definite subject, and as the number of possible systems after all can be but small, therefore also they are themselves the lesser evil.
Much greater is the evil which lies in the pompous retinue of technical terms—scientific expressions and metaphors, which these systems carry