This brings me to the first point I want to make about what this book is not. I am not advocating(提倡) a morality(道德) based(以…作基础) on evolution. I am saying how things have evolved(发展). I am not saying how we humans morally(道德上) ought to behave. I stress this because I know I am in danger of being misunderstood by those people, all too numerous(许多的), who cannot distinguish(区别) a statement of belief(相信) in what is the case from an advocacy of what ought to be the case.
