Evolution is the gradual development, growth or advancement of things or organisms.
The philochron evolution (PE) is the principle that reduces all changes to evolution (perceptible) and duration (imperceptible). The PE is present in all sectors of reality, natural and social.
There are two classes of PE: outer and inner. The outer PE can be monotonous and variable. The inner PE are the changes that matter undergoes at the atomic and subatomic level.
Examples of monotonous PE are: heartbeat, river current, etc. Examples of variable PE are: bird flight, human behavior, cloud formation, etc.
Let's think about a movie. The movie has an evolution and a duration (time). We perceive the evolution, but not the duration.
The measurement of time or duration is purely mathematical. Different from time are, for example, length (we see one meter) and mass (we feel one kg).