His perhaps most widely known work, "Ethics: Inventing Right and Wrong", bluntly begins with the sentence "There are no objective values". He uses several arguments to support this claim. He argues that some aspects of moral thought are relative, and that objective morals require an absurd intrinsic action-guiding feature. Most of all, he thinks it is very unclear how objective values could supervene on features of the natural world (see the "Argument from queerness"), and argues it would be difficult to justify our knowledge of "value entities" or account for any links or consequences they would have. Finally, he thinks it possible to show that even without any objective values, people would still have reason to firmly believe in them (hence he claims that it is possible for people to be mistaken or fooled into believing that objective values exist). "The Times" called the book "a lucid discussion of moral theory which, although aimed at the general reader, has attracted a good deal of professional attention."