Nature contains all forms of energy and matter, (including perceptual phenomena that inhabit a human brain.) Reality is the absolute presence of Nature and is equivalent to absolute Truth. Absolute truth is the same as Reality and is independent of human perception. In an attempt to discover absolute Truth, we must rely on relative accounts (our own and others) to identify or verify Reality. Often the search for truth falls short. Sometimes it succeeds. Knowing the difference between 'half' truths and Reality depends on our accumulated knowledge of Nature, its patterns and principles. Nature, Reality, and Truth are the cornerstones on which our understanding of the Universe is constructed.