  This very point is something that Antoine Arnauld noticed immediately upon reading the Discourse on Metaphysics. (More exactly, Arnauld read only what are now usually presented as brief synopses of the individual sections.) As he wrote to Leibniz, “Since it is impossible that I should not always have remained myself, whether I had married or lived in celibacy, the individual concept of myself contained neither of these two states; just as it is well to infer: this block of marble is the same whether it be at rest or be moved; therefore neither rest nor motion is contained in its individual concept.” (G II 30) Arnauld's point is quite simply that the property of being celibate is not essential to him or to his concept because he would still be Arnauld even if he had married and had children.