The advice, so often associated with Francis Bacon, to get rid of all false pre-conceptions, of all _idola,_ is one which it is easy to mistake in an over-zeal to follow it. That mere negation of prejudices which we call childish innocence is no match for the craft by which Nature seeks to keep or disguise her secrets. The free consciousness, the unbiassed mind, is not the easy result of one great act of renunciation, but the work of continued self-discipline, self-conquest, self-realisation. If you are not to impose upon the thing a pre-conception alien to it, neither must you rashly give yourself away to the thing, or to the first whims which accident puts upon you as the thing. What seems a fact or thing is only a candidate for the post of thing or fact: and its credentials need to be examined, and compared with other evidences. To detect a fact, therefore, is only possible for a tried and tested consciousness which by patience and self-mastery has won the key of interpretation. What Bacon apparently meant--though, as often happens, in his eagerness to combat a prevailing folly, he sometimes overshot himself in statement--was to insist on the eternal wedlock of the mind and things, of things and the mind, as the sole and sufficient condition for the reality of knowledge and truth. The mind may not presume to do without things, or things to domineer the mind;--or the result is a windy and frothy vanity. And the wedlock is eternal: in his own eloquent words, 'the mind itself is but an accident to knowledge[7],' and he might have added, so also are things: for, as he says, 'the truth of being and the truth of knowing is all one': only in the bond of knowledge are things true and real,--being otherwise only 'permanent possibilities,' or possibilities barely even permanent--or not even possibilities. Yet he scarcely realised that his 'due rejections and exclusions' and negations were a fundamental _constitutive_ element in those facts of which he habitually emphasises only the positive side.