The theory of a plenum is as false as that of a void. It is now demonstrated that motion is as impossible in absolute fulness, as it is impossible that, in an equal balance, a weight of two pounds in one scale should sink a weight of two in the other. Now, if every motion absolutely requires empty space, what becomes of Spinoza's one and only substance? How can the substance of a star, between which and us there is a void so immense, be precisely the substance of this earth, or the substance of myself, or the substance of a fly eaten by a spider? Perhaps I mistake, but I never have been able to conceive how Spinoza, admitting an infinite substance of which thought and matter are the two modalities--admitting the substance which he calls God, and of which all that we see is mode or accident--could nevertheless reject final causes. If this infinite, universal being thinks, must he not have design? If he has design, must he not have a will? [Illustration: Descartes.] Spinoza says, we are modes of that absolute, necessary, infinite being. I say to Spinoza, we will, and have design, we who are but modes; therefore, this infinite, necessary, absolute being cannot be deprived of them; therefore, he has will, design, power. I am aware that various philosophers, and especially Lucretius, have denied final causes; I am also aware that Lucretius, though not very chaste, is a very great poet in his descriptions and in his morals; but in philosophy I own he appears to me to be very far behind a college porter or a parish beadle. To affirm that the eye is not made to see, nor the ear to hear, nor the stomach to digest--is not this the most enormous absurdity, the most revolting folly, that ever entered the human mind? Doubter as I am, this insanity seems to me evident, and I say so. For my part, I see in nature, as in the arts, only final causes, and I believe that an apple tree is made to bear apples, as I believe that a watch is made to tell the hour. I must here acquaint the readers that if Spinoza, in several passages of his works, makes a jest of final causes, he most expressly acknowledges them in the first part of his "Being, in General and in Particular."