Stephen Hawking. A brief history of time (№ 149840)

The computer memory is, roughly speaking, a device containing elements that can be in one of two States. A simple example of such a device is abacus the ancient abacus. In its simplest form is a set of horizontal wires, each of which is mounted the bead. Each bead is in one of two positions. Until the memory of the computer nothing is entered, it is in a chaotic state in which both the possible locations of the beads are equiprobable (the beads on the wires distributed randomly). After the memory proteinopathy system, which we must remember, her condition will be very specific, depending on the state of the system. (Each bead on the accounts will be either in the right or in the left end of the wire). So, computer memory has moved from disorder to an ordered state. But in order to be sure that the memory is in the right state, you have to spend a certain amount of energy (for example, for throwing of beads or the power of the computer). This energy goes into heat and thereby increase the degree of disorder in the Universe. It can be shown that this increase in disorder is always greater than the increase in the orderliness of the memory itself. The need for a computer cooling fan, says that when the computer writes something to the memory, the total disorder in the Universe still increases.
The direction of time in which a computer remembers the past is the same, in which disorder increases.
Consequently, our subjective sense of direction of time, the psychological arrow of time is defined in our brain by the thermodynamic arrow of time. Like a computer, we must remember things in the same order in which entropy increases. The second law of thermodynamics becomes almost trivial. Disorder increases with time because we measure time in the direction in which disorder increases. It's hard to argue with this logic!