any thing; and that the language of every philosopher should be the following: "This now seems so; I am conscious of it; I know nothing further; I experience a necessity of believing it, but perhaps this belief is a pure illusion; I know nothing of the external world; I know nothing either of the internal world; all knowledge is denied me; I myself am only a succession of phenomena which pass away and disappear; an irresistible necessity impels me to believe that these phenomena have a common tie, but this tie is nothing; because when a phenomenon disappears nothing is before it; if I acknowledge any reality, no matter what, I fall into the substantiality of the soul, which I have resolved not to admit; all is illusion, all is nothing, because, as I am not even certain of the facts of consciousness, I am not certain even of the illusion." Who can encounter such consequences? CHAPTER XI. SIMPLICITY OF THE SOUL. 72. I have confined myself in the preceding chapters to proving the substantiality of the soul; to do which it was only necessary to demonstrate by the testimony of consciousness that there is within us a permanent reality, the subject of the modifications which we experience. I shall now demonstrate that this substance is simple. To proceed methodically, let us fix the meaning of the word _simple_. When many beings are united and form a collection, the result is called a composite being; so that there is a true composition wherever beings substantially distinct are united; the band which unites them may be of different species, which produces the diversity of compositions. Simplicity is opposed to composition; the idea of simplicity essentially excludes the idea of composition; as this last includes a _number_ of distinct things which are united to form a whole, the idea of simplicity essentially excludes the idea of number of things united to form a whole. Therefore the simple is strictly one, and there is simplicity in a substance when it is not a collection of substances. When, therefore, we say the substance of the soul is simple, we mean that it is not a collection of substances, but one substance. 73. The idea of simplicity thus determined with exactness, let us see if it belongs to our soul. As the soul is not given us in intuition after the manner of sensible things, and we only know it by the presence of the internal sense, and by the phenomena which we experience in the depths of our consciousness, we must examine these two sources to see if we can find simplicity in them.