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2.3 Arrows of time
From a broad scientific perspective, there exists three arrows of time namely thermodynamic arrow of time, psychological arrow of time and cosmological arrow of time for the macroscopic processes that exist in nature. The thermodynamic arrow of time refers to the direction of time in which disorder (the total entropy) always increases in any process, thereby conveying the irreversibility of macroscopic process  as expressed by the following equation for a closed system:
The most striking feature of these three arrows is that all of them point towards the same direction and all of them are interlinked to one another for synchronized behaviour of natural phenomena.
Conventional examples for this case are hot coffee becomes cold,things wear out and run down,and an ice cube melting to change from an orderly crystal state to a disordered puddle of
water. The second arrow of time refers to the psychological arrow indicating the direction of time in which one remembers the past only but not the future. The third arrow of time refers to the cosmological arrow of time in which the Universe always expands but does not contract . The most striking feature of these three arrows is that all of them point towards the same direction and all of them are interlinked to one another for synchronized behavior of natural phenomena.The case of psychological and thermodynamic arrow of time both having the same direction is argued based on a computer memory system that involves the storage of memory through organized hierarchical steps like in an abacus system . However, the overall order of the memory system in due course of time is lower than the increase of the disorder of the system in the form of heat dissipated. In other words, both human memory or computer memory remember the past in the direction in which disorder increases.In a similar way, the basic reason behind the same direction of time in which both cosmological and thermodynamic arrow of time point is being reasoned . In a contracting universe (unlike ours which is an expanding one), disorder decreases in the gaining direction. However, intelligent life can be observed to be nonexistent in a contracting universe. This is due to the fact that intelligent beings need food to survive and the fate of energy cycle in an ecosystem involves energy loss as heat and no energy recycle (Figure 3). In other words, intelligent life demands the existence of expanding universe for its survival in nature.