these impressions, expressed by the word "is." And as the object does not resolve itself into three parts, but is to all intents and purposes one, and as there can be nothing in the object to correspond to the act of judging expressed by the word "is," we conclude that the power of analysis of the simple impression into three, together with that of judging upon it, belong to the mind itself. Further, as we have no reason to think that this object created the two powers, or did more than call them into action, we conclude that they were present a priori, that is, prior to the impression from without. And again, for the same reason that they are not found in this object of sense,—that is, because they decompose it into many parts and judge upon its parts, which no object can do for itself. -we conclude that they were not learnt from any object we may have seen before; and therefore they are absolutely a priori, they are independent of all experience.*

*The various modes of expressing the antithesis between thoughts and things are here exhibited in a tabular form:

§ 33. Hence we may understand the importance which attaches to Leibnitz's well-known comment on the maxim of the school of Locke*; to the nihil est in intellectu, quod non fuerit in sensu, he adds-nisi intellectus ipse. The mind does not simply receive the impressions of the senses, like the passive surface of a mirror; it groups them, judges about them, separates their qualities from each other, and draws inferences about the qualities which like objects, hitherto unknown, may be expected to have. But qualities, classes, inferences, are not objects of sense, however they may reside in or be drawn from those objects. They have no separate existence out of the mind; whilst, within it, they are perfectly distinct. This transmutation of objects of sense into their elements must therefore be the work of the mind alone. It is a law of the intellect itself, and never was nor can have been in the sensuous impressions we have received.

§ 34. Pure Logic treats only of those laws or conditions to which objects of sense are subjected in the mind and hence it is called an a priori science. It unfolds the laws of the intellectus ipse, and gives no

*Leibnitz, Nouveaux Essais, ii. 1. p. 223, Erdmann's Ed. Locke himself admits "ideas of reflection," gained by observing the mind's own actions, besides "ideas of sensation." On Hum. Under. II. v. 1.

account of the representations of the senses as such. It will enumerate, for instance, all the different kinds of judgments which can be formed, but will not pretend to decide upon the truth of any one judgment respecting something which is now before the eyes. As the laws of the understanding are few and invariable, whilst the phenomena in the world around us appear, from our imperfect knowledge of their complicated laws, very uncertain, Logic is far less liable to error than those sciences which have to do with external facts. Thus the truth that "if A is B and B is C, then A must be C," cannot be denied, whatever we suppose these letters to represent. The formula is universal and necessary; it was so in the days of Aristotle, and will be as long as there remains upon the face of the world one mind to think. But an à posteriori science a science of external factslike Astronomy, though using demonstration, depends upon observation, and the accuracy of its calculations is in a direct ratio to our opportunities of observing all the circumstances which may affect them. can never be a necessary truth that after each interval of two hundred and twenty-three lunations the sun will be eclipsed: grounded only upon facts, when ever some convulsion shall be prepared by the Creator to disturb them, its prediction will fail. Calculations of the period of the return of comets have sometimes failed, because of our defective means of

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observation; thus the return of the comet of 1770 was promised in five years and a half; it falsified the prediction, and never returned at all.

This view of Logic as an à priori science, it is hoped, will meet with a pretty general assent; and we purposely abstain from touching the great question of Metaphysics-how much of our knowledge is from the mind itself and how much from experience. The conflicting opinions upon this matter will never be reconciled, and perhaps the best service which philosophy could receive would be rendered by marking out the region which must be mutually ceded by the opposite schools.*

§ 35. By explaining some of the various names bestowed on Logic by those who have treated it, we shall have a clear view of the position they in

*Before leaving the subject, it must be noticed that the term à priori has undergone important changes of meaning. In Aristotle's philosophy the general truth is "naturally prior" (TрÓTEρOV TY PÚσe) to the particular, and the cause to the effect; but since we know the particular before the universal, and the effect before we seek the cause, the particular and the effect are each "prior in respect to us" (πроτероν πрòя пuâs). Anal. Post. I. ii.; Top. VI. iv.; Metaphys. v. (▲) xi. p. 1018. Ed. Berol. Following this, the Schoolmen call the argument which proceeds from cause to effect, à priori demonstration. But with Hume (Sceptical Doubts) à priori has the sense given in the text, which Kant has fixed in the language of philosophy. See Trendelenburg's Excerpta, p. 81., Ed. 1.; Sir W. Hamilton's Reid, p. 762.

tended it to occupy. (a.) It has been called the Architectonic Art, by which is meant that it occupies the same position with regard to the sciences and arts in general, that Architecture does to the labours of the carpenter, the mason, the paviour, the plumber and the glazier; arranging and directing them indeed so as to contribute to one common end, but not necessarily knowing the details of their business, nor putting its hand to their toil. Used by Plato as an illustration (Polit. 259. E.) the word Architectonic was adopted by Aristotle as a general name for all arts which kept other arts subservient to them (Eth. Nic. 1. i.). And as the rules of Logic must be obeyed not by one art or the other but by every one, other writers were naturally led to apply the name Architectonic to it especially. The same supremacy is vindicated to Logic in another of its names; by the followers of Aristotle it was called (b.) the Instrument (or Organon) and the Instrument of Instruments. Aristotle himself did not affix the name of Organon to that collection of logical treatises that now bears the name; but he speaks of our possessing in ourselves two instruments (öpyava) by which we can employ external instruments, the hand for the body and reason for the soul; and adds that science is the instrument of reason* ; and it is

* Arist. Probl. A. 5. (955. b.) De An. г. 8. (432. a. 1.) Polit. A. 3. (1253. b.)