It is almost impossible systematically to constitute a natural moral law. Nature has no principles. She furnishes us with no reason to believe that human life is to be respected. Nature, in her indifference, makes no distinction between good and evil.

In this passage France rejects the idea that morality can be read directly off “nature” as a set of built-in principles. Nature, he argues, is descriptive rather than normative: it shows what happens, not what ought to happen. Because natural processes are indifferent to suffering and make no moral discriminations, appeals to “natural law” cannot by themselves justify duties like respecting human life or distinguishing good from evil. The implication is that ethical norms must be grounded in human reason, sympathy, social agreement, or culture—not in the mere fact of how the world works. It is also a warning against using “nature” rhetorically to sanctify violence, hierarchy, or cruelty.