A central theme of this book is that the main problems of philosophy and certainly the main traditional problems in the theory of knowledge, concern the space between language and the world. Professor Danto distinguishes between descriptive concepts, concerned with saying how the world is and semantic concepts, which have to do with the application of descriptions of the world. Failure to make these distinctions is responsible for a class of seemingly irresolvable disputes over the foundations of knowledge; but when the distinction is appreciated, a plausible philosophical theory of what it is to know the world can be framed which is free from the standard scepticisms.