This book is an exploration of various themes common to the broad tradition of Western philosophy. What do we mean by a relation? Is a relation a transcendental object or something only operative in the world of concrete things? What is the difference between universal and particular? Is there clarity in the way we represent an object or is clarity only in the way a thing is composed? What is the difference between knowledge before the fact (a priori) and knowledge after the fact (a posteriori)? These are all questions that pertain to our understanding of who we are and of the world we live in. We also touch broader issues, such as the relation between space and time and art and nature, with particular emphasis on modern developments in physics and biology. The fixity of space and time is something that has come to be questioned as is the fixity and origin of the human species. These are dealt with in a way that is conformable to modern thinking yet which remains sensitive to broader historical concerns.