We do know things about ethics. We know that human life is important and valuable. We know that people have rights; rights to take their own paths in life. We know it is ethically wrong to violate those rights. We know we have obligations to our family, to our friends, to humanity at large. I take that to be an important kind of knowledge, but a normal kind of knowledge.Not having heard the lecture series, I don't know where Grim eventually comes down on this question, but I'd say two things about it here. First, I'm not sure we do know the things Grim says we know, although it's certainly true that many of us believe those things. Secondly, in order for those beliefs we hold to be knowledge they have to have some warrant or justification, and that leads us to a crucial question: What warrant do we have for thinking that our beliefs - for example, that others have rights - are true beliefs, i.e. knowledge?
The question, as I see it, is not whether we have that kind of knowledge. The question is a reflective question about what kind of knowledge that is.
If someone claims that other people have rights then we might ask where those rights come from. If our rights are inherent in us because we're human then it'd be wrong for anyone to deprive us of them, but where do "inherent" rights come from, and what do we mean when we say that depriving someone of an inherent right is "wrong"?
If the human species is nothing other than the end-product of a blind, naturalistic process of development that occurred over eons of time then to say something is wrong is to say little more than "I don't like it", but if "wrong" is just what someone else doesn't like then why should anyone care about refraining from doing what others don't like if it doesn't suit them to do so?
Philosopher David Hume in his book The Treatise of Human Nature came to the conclusion that right and wrong are simply whatever wins the general approbation or disapprobation of one's fellows, but if that's all we mean by right and wrong then the terms are synonymous with "socially fashionable". To accuse someone of doing wrong is like accusing them of gaucherie because they slurp their soup. Such behavior may be unconventional and distasteful, but it's not wrong. When we say that child abuse is wrong, however, we surely want to say more than that it's unconventional and distasteful behavior. We want to say that it's evil.
Ethics are indeed self-evident, and we do have intuitive knowledge of right and wrong, but only because, in the words of Thomas Jefferson, we've been endowed by our Creator with a law, in the words of St. Paul, "written on our hearts". That law, being the gift of a perfectly good and wise being who will ultimately hold us accountable to it, is the source of all our moral understanding.
It's binding upon us only because it's bestowed by a personal being. If it were merely the product of impersonal evolutionary forces we would be no more obligated to observe it than we are obligated to refrain from flying in an airplane because it flouts the law of gravity.
If, as Grim says, we know that human life is important and valuable, that people have rights; rights to take their own paths in life, that it's ethically wrong to violate those rights, and that we have obligations to our family, to our friends, and to humanity at large, then we are tacitly acknowledging that there must be a God who has bestowed those rights and obligations upon us.
Either that or we're trying to hold on to the belief in right and wrong while discarding the only suitable foundation for that belief. It's like pulling the table out from under the dinner setting and expecting the dishware to all remain in place.
