CHAPTER I.

INTRODUCTION.

§ 1. _The Method._

The divine Plato and the marvellous Kant unite their mighty voices in recommending a rule, to serve as the method of all philosophising as well as of all other science.[11] Two laws, they tell us: the law of _homogeneity_ and the law of _specification_, should be equally observed, neither to the disadvantage of the other. The law of _homogeneity_ directs us to collect things together into kinds by observing their resemblances and correspondences, to collect kinds again into species, species into genera, and so on, till at last we come to the highest all-comprehensive conception. Now this law, being transcendental, _i.e._ essential to our Reason, takes for granted that Nature conforms with it: an assumption which is expressed by the ancient formula, _entia præter necessitatem non esse multiplicanda_. As for the law of _specification_, Kant expresses it thus: _entium varietates non temere esse minuendas_. It requires namely, that we should clearly distinguish one from another the different genera collected under one comprehensive conception; likewise that we should not confound the higher and lower species comprised in each genus; that we should be careful not to overleap any, and never to classify inferior species, let alone individuals, immediately under the generic conception: each conception being susceptible of subdivision, and none even coming down to mere intuition. Kant teaches that both laws are transcendental, fundamental principles of our Reason, which postulate conformity of things with them _à priori_; and Plato, when he tells us that these rules were flung down from the seat of the gods with the Promethean fire, seems to express the same thought in his own way.

[11] Platon, "Phileb." pp. 219-223. "Politic." 62, 63. "Phædr." 361-363, ed. Bip. Kant, "Kritik der reinen Vernunft. Anhang zur transcend. Dialektik." English Translation by F. Max Müller. "Appendix to the Transc. Dialectic." pp. 551, and _seqq._

§ 2. _Application of the Method in the present case._

In spite of the weight of such recommendations, I find that the second of these two laws has been far too rarely applied to a fundamental principle of all knowledge: _the Principle of Sufficient Reason_. For although this principle has been often and long ago stated in a general way, still sufficient distinction has not been made between its extremely different applications, in each of which it acquires a new meaning; its origin in various mental faculties thus becoming evident. If we compare Kant's philosophy with all preceding systems, we perceive that, precisely in the observation of our mental faculties, many persistent errors have been caused by applying the principle of homogeneity, while the opposite principle of specification was neglected; whereas the law of specification has led to the greatest and most important results. I therefore crave permission to quote a passage from Kant, in which the application of the law of specification to the sources of our knowledge is especially recommended; for it gives countenance to my present endeavour:--

"It is of the highest importance to _isolate_ various sorts of knowledge, which in kind and origin are different from others, and to take great care lest they be mixed up with those others with which, for practical purposes, they are generally united. What is done by the chemist in the analysis of substances, and by the mathematician in pure mathematics, is far more incumbent on the philosopher, in order to enable him to define clearly the part which, in the promiscuous employment of the understanding, belongs to a special kind of knowledge, as well as its peculiar value and influence."[12]

[12] Kant, "Krit. d. r. V. Methodenlehre. Drittes Hauptstück," p. 842 of the 1st edition. Engl. Tr. by F. M. Müller. "Architectonic of Pure Reason," p. 723.

§ 3. _Utility of this Inquiry._

Should I succeed in showing that the principle which forms the subject of the present inquiry does not issue directly from _one_ primitive notion of our intellect, but rather in the first instance from _various_ ones, it will then follow, that neither can the necessity it brings with it, as a firmly established _à priori_ principle, be _one_ and the _same_ in all cases, but must, on the contrary, be as manifold as the sources of the principle itself. Whoever therefore bases a conclusion upon this principle, incurs the obligation of clearly specifying on which of its grounds of necessity he founds his conclusion and of designating that ground by a special name, such as I am about to suggest. I hope that this may be a step towards promoting greater lucidity and precision in philosophising; for I hold the extreme clearness to be attained by an accurate definition of each single expression to be indispensable to us, as a defence both against error and against intentional deception, and also as a means of securing to ourselves the permanent, unalienable possession of each newly acquired notion within the sphere of philosophy beyond the fear of losing it again on account of any misunderstanding or double meaning which might hereafter be detected. The true philosopher will indeed always seek after light and perspicuity, and will endeavour to resemble a Swiss lake--which through its peacefulness is enabled to unite great depth with great clearness, the depth revealing itself precisely by the clearness--rather than a turbid, impetuous mountain torrent. "_La clarté est la bonne foi des philosophes_," says Vauvenargues. Pseudo-philosophers, on the contrary, use speech, not indeed to conceal their thoughts, as M. de Talleyrand has it, but rather to conceal the absence of them, and are apt to make their readers responsible for the incomprehensibility of their systems, which really proceeds from their own confused thinking. This explains why in certain writers--Schelling, for instance--the tone of instruction so often passes into that of reproach, and frequently the reader is even taken to task beforehand for his assumed inability to understand.

§ 4. _Importance of the Principle of Sufficient Reason._

Its importance is indeed very great, since it may truly be called the basis of all science. For by _science_ we understand a _system_ of notions, _i.e._ a totality of connected, as opposed to a mere aggregate of disconnected, notions. But what is it that binds together the members of a system, if not the Principle of Sufficient Reason? That which distinguishes every science from a mere aggregate is precisely, that its notions are derived one from another as from their reason. So it was long ago observed by Plato: καὶ γὰρ αἱ δόξαι αἱ ἀληθεῖς οὐ πολλοῦ ἄξιαί εἰσιν, ἕως ἄν τις ἀυτὰς δήσῃ αἰτίας λογισμῷ (_etiam opiniones veræ non multi pretii sunt, donec quis illas ratiocinatione a causis ducta liget_).[13] Nearly every science, moreover, contains notions of causes from which the effects may be deduced, and likewise other notions of the necessity of conclusions from reasons, as will be seen during the course of this inquiry. Aristotle has expressed this as follows: πᾶσα ἐπιστήμη διανοητική, ἢ καὶ μετέχουσά τι διανοίας, περὶ αἰτίας καὶ ἀρχάς ἐστι (_omnis intellectualis scientia, sive aliquo modo intellectu participans, circa causas et principia est_).[14] Now, as it is this very assumption _à priori_ that all things must have their reason, which authorizes us everywhere to search for the _why_, we may safely call this _why_ the mother of all science.

[13] "Meno." p. 385, ed Bip. "Even true opinions are not of much value until somebody binds them down by proof of a cause." [Translator's addition.]

[14] Aristot. "Metaph." v. 1. "All knowledge which is intellectual or partakes somewhat of intellect, deals with causes and principles." [Tr.'s add.]

§ 5. _The Principle itself._

We purpose showing further on that the Principle of Sufficient Reason is an expression common to several _à priori_ notions. Meanwhile, it must be stated under some formula or other. I choose Wolf's as being the most comprehensive: _Nihil est sine ratione cur potius sit, quam non sit._ Nothing is without a reason for its being.[15]

[15] Here the translator gives Schopenhauer's free version of Wolf's formula.