Atheism and moral scepticism.

Many philosophers have argued, and continue to argue, that if atheism is true
- if there is no transcendent creator of the universe or parts of it (most importantly,
no transcendent creator of life on earth and of human beings) - then there are no
moral truths. In this essay, I argue for the related but different thesis that atheists
have reason to accept the claim that all of their moral beliefs are unwarranted (or
unjustified), a claim I refer to as "moral scepticism".
After explaining atheism and providing some metaethical preliminaries, I
consider some empirical findings that might be thought to support the idea that
everyone should embrace moral scepticism regardless of whether they are atheists; I
argue that they do not support that idea. Going on to discuss Darwinism and morality,
I develop what I call the argument for atheistic Darwinian moral scepticism. While
this argument gives atheists reason to embrace moral scepticism, advocates of theism
- the most widely defended alternative to atheism - do not have reason to consider
their moral beliefs unwarranted, or at least not the same reason that atheists do.
Acknowledging that atheists could avoid the argument for atheistic
Darwinian moral scepticism if they can maintain an expressivist (or quasi-realist)
understanding of the function of moral thought and discourse, I nevertheless argue
that there is good reason to believe that expressivism is false. Lastly, I consider some
consequences of atheists embracing moral scepticism, arguing against the moral
fictionalist idea that moral sceptics can simply pretend to have warranted moral
beliefs and carry on much as before. I also suggest that atheists will not be able to
endorse two kinds of argument that many of them have wanted to endorse: the
argument from evil against theism and moral arguments against purported divine
revelations.