Gompertz hypothesis

Gom·pertz hy·poth·e·sis

(gom'pĕrtz),
a theory that the force of mortality increases in geometric progression, being based on the assumption that the average exhaustion of an individual's power to avoid death is such that at the end of equal infinitely small intervals of time the individual loses equal proportions of the power to oppose destruction that were available at the commencement of each of these intervals.

Gompertz,

Benjamin, English actuary, 1779-1865.
Gompertz hypothesis - a theory that the force of mortality increases in geometrical progression.
Gompertz law - after age 35-40, the increase in mortality with age tends to be logarithmic.