A discussion (however far from technical completeness) of the polemical element in St. John's Epistle, probably seems likely to be destitute of interest or of instruction, except to ecclesiastical or philosophical antiquarians. Those who believe the Epistle to be a _divine_ book must, however, take a different view of the matter. St. John was not merely dealing with forms of human error which were local and fortuitous. In refuting _them_ he was enunciating principles of universal import, of almost illimitable application. Let us pass by those obscure sects, those subtle curiosities of error, which the diligence of minute research has excavated from the masses of erudition under which they have been buried; which theologians, like other antiquarians, have sometimes labelled with names at once uncouth and imaginative. Let us fix our attention upon such broad and well-defined features of heresy as credible witnesses have indelibly fixed upon the contemporaneous heretical thought of Asia Minor; and we shall see not only a great precision in St. John's words, but a radiant image of truth, which is equally adapted to enlighten us in the peculiar dangers of our age. Controversy is the condition under which all truth must be held, which is not in necessary subject-matter--which is not either mathematical or physical. In the case of the second, controversy is active, until the fact of the physical law is established beyond the possibility of rational discussion; until self-consistent thought can only think upon the postulate of its admission. Now in these departments all the argument is on one side. We are not in a state of suspended speculation, leaning neither to affirmation nor denial, which is _doubt_. We are not in the position of inclining either to one side or the other, by an almost impalpable overplus of evidence, which is _suspicion_; or by those additions to this slender stock, which convert suspicion into _opinion_. We are not merely yielding a strong adhesion to one side, while we must yet admit, to ourselves at least, that our knowledge is not perfect, nor absolutely manifest--which is the mental and moral position of _belief_. In necessary subject-matter, we know and see with that perfect intellectual vision for which controversy is impossible.[69] The region of belief must therefore, in our present condition, be a region from which controversy cannot be excluded.