"Subjective experience must inform physics and philosophy, but it should be assessed carefully. Time is a contentious topic in physics. Some physicists, such as Julian Barbour, argue that it doesn’t even exist. Others, such as Carlo Rovelli, hold that it arises as a secondary effect of deeper quantum processes. Yet others, such as Lee Smolin, maintain that time is the sole fundamental dimension of nature. And because the laws of physics are time-symmetrical, much debate has gone into figuring out why we seem unable to travel back in time. All this theorizing is motivated by—and attempts to make sense of—our subjective experience of the forward flow of time ... (read more)