A proportion of the aging research community think aging to be at least partially a programmed phenomenon, rather than an accumulation of damage, and thus something to be primarily manipulated by changing the operation of our metabolism. Here is an argument for that viewpoint from researcher Michael Rose: "I should be clear that my present view is also not one generally held, at least not yet, even by most evolutionary biologists who work on aging. Like them, I spent more than thirty years thinking that William Hamilton's declining forces of natural selection, which he published in 1966, showed that evolution by natural selection would allow cumulative processes of physiological deterioration to proceed unchecked, provided they killed off their victims at sufficiently late ages. ... By 1994, I was thinking that perhaps evolutionary biologists had misconceived the problem of the evolution of aging. Perhaps it was NOT natural selection just letting go, but something that specifically tracked Hamilton's forces of natural selection. This led me to convince Larry Mueller to do some explicit simulations of evolution, simulations in which we looked at what happened at very late ages, long after Hamilton's forces of natural selection bottom out and stabilize. What the simulations generated were late-life plateaus in mortality ... we then checked how changes in Hamilton's forces would change the age at which mortality plateaus occur, based on explicit simulations. These simulations showed that changing the last age of reproduction in a biological population, the parameter that Hugh Hefner is working on as I write, would tune the age at which mortality rates would plateau."