Abstract: I identify the metaphysical sources d’Holbach uses to build two ideas in the Système de la nature. I show that the idea of an intrinsic activity of nature is obtained by reference to the way Toland interprets Newtonian physics. I also analyze how the thesis of the heterogeneity of matters is grounded on an interpretation of the Leibnizian principle of Indiscernibles. This method of borrowing certainly produces tensions in the System, but it also leads to the possibility of identifying different “materialism models” in it.
