Time is the foremost illusion of science. Long time ago Parmenides taught that it is indeed so. Then came   Newton who believed that  time is as real as space. Both are containers for events and are as real as the object they contain. Despite the teaching of  Leibnitz that  time is  a way to describe change, modern physics regards time as an independent ontological entity which really exists and controls us.

What we perceive is change. In ancient civilizations astrologers studied change in heaven and discovered the way of  heavenly bodies.   They were interested also in the rate of change, which they expressed in terms of days, seasons or years. Yet these heavenly clocks were crude.  Then one day the first water clock was invented and the measurement of the rate of change of events improved. With time this and other   clocks became an essential factor in the evolution of knowledge.   

Descartes introduced a mathematical framework within which change is studied. Three space and one time axis.  The last differs  inherently from the other  since it is supposed to drive   events,   which is deeply rooted  in the differential calculus. Take the metaphysical fraction ds/dt  known as infinitesimal and try to invert it to dt/ds which looks like nonsense, Why? Since only time drives events. Whoever observed space to drive anything?  The creation of ds/dt  bred  the time illusion which dominates science  today. Serious truth lovers were even ready to accept that Newton’s time flows also backward. Why should Newton’s laws make such a contra-intuitive suggestion?  Simply because eliminating the back flow of time from  his equations would introduce an unpleasant discontinuity which Newton did not bother to handle. After all discontinuities are the main threat to the differential calculus.

And then came entropy with its time arrow directed forward. Entropy has two disturbing properties:  It disobeys Newton’s laws and its rate cannot be measured with Newtonian chronometers. Might  these two representations of time be united under a more general one? After all  these theories are only two models for interpreting change, and there are more, each  with its individual time and clock. Like the relativity theory which may be regarded as a set of instructions how to set your clock when traveling

Yet for some physicists, relativity theory has an unpleasant aspect. Time travel back in time is somewhat compromised. Fortunately it can be easily resolved  with additional dimensions. With nine dimensions at hand and a brane, time travel is as easy as it can be.   Or  take Stephen Hawking’s  A Brief History of Time. Shouldn’t it be   broadened   a bit and tell us about the History of Clocks in Time?

I started contemplating time, when realizing that medical doctors  measure events in the body with a wrong time piece, the  Newtonian clock,  while in reality our clock is different. Take two of your friends with the same age. One looks younger, and the other somewhat older. Their Newtonian ages are  the same, yet their biological clocks tic at different rates

Since doctors measure disease progression with Newtonian clocks their prognosis is generally wrong particularly in cancer when some doctors assure their patients that their time is running out, while the patient’s  inner clock  disobeys  their verdict

Long before Newton and Parmenides, Hindu philosophers realized that time is an illusion. The almighty Brahman is timeless, and  lets his assistant by the name of Maya to spread the illusion of time.