 Yet the original inspiration for the Enlightenment was the new physics, which was mechanistic. If nature is entirely governed by mechanistic, causal laws, then it may seem that there is no room for freedom, a soul, or anything but matter in motion. This threatened the traditional view that morality requires freedom. We must be free in order to choose what is right over what is wrong, because otherwise we cannot be held responsible. It also threatened the traditional religious belief in a soul that can survive death or be resurrected in an afterlife. So modern science, the pride of the Enlightenment, the source of its optimism about the powers of human reason, threatened to undermine traditional moral and religious beliefs that free rational thought was expected to support. This was the main intellectual crisis of the Enlightenment. 