Subjective notion, often claiming that now is dependent on one's Philosophers in the opposing camp regard the present as a The future is not, so that the present consists in something like theД¬oming into being of determinate reality. Others take the view that the past is real in a way that Well, sharing Augustine's view that the past and the future are Some members of this camp give the present ontological priority, as Reality, and interpret the present moment as the marker or leading edge Those who regard the passage of time as an objective feature of Philosophers tend to be divided into two camps. These have not changed much since the time of Saint Augustine In a book entitled Time's Arrow and Archimedes' Point theДescribes well the ``stock philosophical debates about 'What is time? If nobody asks me, I know but if I were desirous to explain it to one that should ask me, plainly I know not.' Understand, whatever is meant by that loaded word 'understand', what Time is arguably among the most primitive concepts we have-there canД«e no action or movement, no memory or thought, except in time. 4 Time evolution of macrostates: An example.These ideas also explain most other arrows of time - in particular why do we remember the past but not the future? This apparent paradox is due to Maxwell, Thomson and (particularly) Boltzmann. Time-irreversible behavior of our everyday world? The resolution of Microscopic components of material systems, give rise to the observed Way: how can time-reversible motions of atoms and molecules, the Video of an egg splattering run backwards look ridiculous? Put another Run backwards in time, why don't we observe them doing so? Why does a Turn leads to a great puzzle - if the laws of nature permit all processes to be Make no such distinction between the past and the future. Therefore very surprising that the relevant fundamental laws of nature These processes all move in one direction in time - they areД¬alled 'time-irreversible' and define the arrow of time. Unsplatter waves break but do not unbreak we always grow older, never Milk spills but doesn't unspill eggs splatter but do not The arrow of time expresses the fact that in the world about us the past is distinctly different from the future. Lebowitz, Department of Mathematics and Physics, Rutgers University, NJ

Reverse entropy