Some philosophers have attempted to ground an objective morality without God.

They have proposed dozens of theories: utilitarianism, secular humanism, etc.

Most rest on a criterion chosen by man himself.

Here is the example of utilitarianism:

In order to call their theory objective or absolute, they use different definitions than those set out on the previous page, but at that point, they are no longer speaking of the same thing.

There are a few exceptions, such as Kant, who do not build their morality on a criterion chosen by man.

According to him, morality is an objective and universal law, accessible through reason.

Even supposing that this law exists, how can we access it?

Kant answers: through reason, which he believes to be objective and universal.

The problem is that neither the postulate of an "objective Reason" nor the existence of a morality as a universal law is proven.

Worse still, even if these points were proven, this would still not answer the question of what happens if someone does evil without being seen.

Finally, all these theories, whether based on a criterion or on reason, face a challenge posed by neo-Darwinism.

If our moral intuitions and our reason are the product of random mutations selected for survival, what guarantees that they lead us to an objective moral truth?