Abstract
A great deal of progress has recently been made in characterizing the “mechanisms of aging.” A comparison with the mechanisms of development shows that the two sets of mechanisms are different; nevertheless, mechanisms of aging are conditioned by what happens during development. Aging and development also share some characteristics, such as a similar difficulty in attributing a precise temporal boundary to these processes. Other characteristics seem more specific to aging, such as the role of external (to the organism) and stochastic events in its progression. In fact, both development and aging are historical processes with a mixture of stochastic events and deterministic processes, the ratio of the two being different in each process. Therefore, it is concluded that aging does not fit with a broad, lifelong conception of development.