“Life is a series of natural and spontaneous changes.” Lao Tzu, VI century B.C.
Aging is one of the first, important and unavoidable experiences in human life. There are various theories describing the cause of aging. Most of them are purely biological. It seems that the fundamental, real cause of aging as a phenomenon is more likely to be thermodynamic. The aging process is continuous, consecutive change of the state of the biological system caused by the general tendency of entropy to increase. All biological, morphological, and structural changes occur as a consequence of the entropy rise. The same cause forces an object, bacteria, and a human to age. It is the fundamental natural (Thermodynamic) laws that makes us and surrounding objects, and in general, the whole Universe to change the system’s state and to get older. (1)
Entropy is thus the parameter that is related to all others and describes aging in the best manner. In the beginning, entropy change appears as a consequence of accumulation of matter (growth). Later, decomposition and configurational changes dominate, as a consequence of various chemical reactions (free radical, decomposition, fragmentation, accumulation of lipofuscin-like substances…)(2)
Entropy is one of the most important concepts in physics and in information theory. Informally, entropy is a measure of the amount of disorder in a physical, or a biological system.
It is a parameter that characterizes the chaotic motion of particles.
It is manifested by a degree of molecular, atomic and ionic disorder or chaos.
The higher the entropy of a system, the less information we have about the system. Hence, information is a form of negative entropy.(3)
Entropy characterizes the average amount of information contained in a given subject.
In dissipative biological systems, entropy and its variation between order and chaos is the main driver of aging process.
System destruction/death in biological systems occurs in two cases:
0. At zero entropy – the system rushes to a point.
1. When the entropy is close to 1, the system dissipates.
The range between 0 and 1 represents a narrow entropy gradient which is dedicated for life.