Jean Paul Sartre, famously asserted that, "Without God, all is permitted." This was supposed to be a quote from Dostoyevsky (1821-1881). This is a misquote. Besides that it is not true. The manifest ignorance and absurdity of Sartre's pronouncement is evident when we reflect that he ignores one of the oldest and best known theories in Western philosophy: Plato's Theory of Forms. For Plato, meaning, value, and morality exist independently of any god or Deity, and this is quite characteristic of Greek philosophy in general.
And the general approach of all Jewish thinkers from Saadia Geon and the Duties of the Heart until the Rambam was firmly on the side of Plato.
With the Rambam things get confusing. He wants to retain Natural law which comes from Saadia Geon and is pretty much stated openly in the Talmud. But he wants to move towards Aristotle away from Plato's form of the Good. I still do not know if anyone has addressed this serious issue in the Rambam.
Dear Dr Ross. Could Aristotle have natural law theory? You write he hold from heteronomous authority. But does that have to be so?
Dr Ross: "Traditionally, Natural Law jurisprudence tends to come from Aristotelians, or at least Thomists. From that, we might suppose that Aristotle could have a natural law theory. But the Thomists don't think of ethics in empirical terms, as did Aristotle. Instead, natural law comes from the Mind of God in what is overall a theistic system. But Aristotle's God doesn't worry about human phronesis (prudence), and his conception of even human "wisdom" (sophia) precludes practical issues or applications. As Aristotle says, ethics is not for the young, because they literally have not learned enough from experience. Yet the old themselves are liable to notice that the young are often the most passionate about justice. And if this passion is often expressed in foolish, destructive, or vicious ways, where is the fault? The old are just as likely to become cynical as wise, or pessimistic rather than dedicated. Aristotle certainly had no political ideals to promote; and he may not have appreciated himself how the institution of "mixed" forms of government he described, as praised by Polybius or James Madison, represented in ideal in its own right, as an accommodation with the ignorance or self-interest of human nature. Even now, a substantial body of political opinion is impatient with checks and balances and divided authority.