In all cases this process involves an element to which nothing corresponds in the Tables of 'Comparence' and 'Exclusion,' namely, the application to the facts of observation of a principle of arrangement, an idea, existing in the mind of the discoverer antecedently to the act of induction.

It may be said that this idea is precisely one of the _naturae_ into which the facts of observation ought in Bacon's system to be analysed.
And this is in one sense true; but it must be added that this analysis, if it be thought right so to call it, is of the essence of the discovery which results from it.

In most cases the act of induction follows as a matter of course as soon as the appropriate idea has been introduced."-- Ellis, _General Preface_, i.

38.
Lastly, not only was Bacon's conception of philosophy so narrow as to exclude one of its greatest domains; for, says Mr.Ellis, "it cannot be denied that to Bacon all sound philosophy seemed to be included in what we now call the natural sciences," and in all its parts was claimed as the subject of his inductive method; but Bacon's scientific knowledge and scientific conceptions were often very imperfect--more imperfect than they ought to have been for his time.

Of one large part of science, which was just then beginning to be cultivated with high promise of success--the knowledge of the heavens--he speaks with a coldness and suspicion which contrasts remarkably with his eagerness about things belonging to the sphere of the earth and within reach of the senses.