John is currently thinking that the sun is bright. Consider his occurrent belief or judgement that the sun is bright. Its content is that the sun is bright. This is a truth- evaluable content (which shall be our main concern) because it is capable of being true or false. In virtue of what natural, scientifically accessible facts does John’s judgement have this content? To give the correct answer to that question, and to explain why John’s judgement and other contentful mental states have the contents they do in virtue of such facts, would be to naturalize mental content.