Our concept of time comes from the cycles of the sun and moon. Our modern concept of time is linear in scope. However the sun and moon are distinctly cyclical in scope. So there are really two concepts of time which the ancient Egyptians articulated as neheh and djet. To the natural philosopher then, time is inherently cyclical in its natural state. To the modern mind that is a conundrum as we are conditioned to believe everything has a beginning as well as perhaps an end.