George Berkeley's investigation of human epistemology remains one of the most respected of its time - this edition contains the treatise in full, complete with the author's preface. One of Berkeley's most important beliefs was that of immaterialism. The meaning being that nothing material exists unless it is perceived by something or someone. Distinct from solipsism - the belief that only the self exists - Berkeley's view is that material items are ideas formed by distinct conscious minds; the concept of reality being simply the summation of shared ideas rather than physical objects fascinated philosophers of the era. Much of Berkeley's philosophy is framed by then-new discoveries in the field of physics. The concepts of color and light thus have a frequent bearing on the overall thesis; disagreeing with Isaac Newton on the subject of space, it was later that Berkeley's contrarian opinions on matters such as calculus and free-thinking gained him further renown.