Makeham hypothesis

Make·ham hy·poth·e·sis

(māk'ăm),
a development of Gompertz hypothesis as to the force of mortality following some mathematical law. Makeham assumed that death was the consequence of two generally coexisting causes: 1) chance; 2) a deterioration or increased inability to withstand destruction. The first of these is constant, the second is an increasing geometric progression.

Makeham,

William Matthew, English actuary, d. 1892.
Makeham hypothesis - assumption that death is the consequence of two generally coexisting causes: (1) chance; (2) a deterioration or increased inability to withstand destruction.