A piece by Aubrey de Grey at the Huffington Post: "as things stand, no amount of insight into age-related pathology can be sufficient to develop outright cures. Some diseases are the end results of aging, just as starvation is the end result of fasting. The nature of aging is such that many age-related infirmities are certain to afflict anyone who lives long enough. And this will remain the case, until a technology is developed which ameliorates the general decrepitude of old age which underlies these diseases. One can, therefore, identify the future direction of medicine by considering the nature of old age itself. What exactly is being taken from us, year after year, from cradle to grave? As time goes by, your hair goes grey, your face gets coarser, you put on weight, you become weaker, more susceptible to disease, and so on. But what do these things have to do with each other? Fortunately, the answer is not so complex as one might anticipate. Most people think of the science of aging as being very incomplete. It is true that aging as a process is not completely understood (biogerontology, the study of aging, involves many competing theories). But the state of disrepair that aging leaves people in can be observed directly, and in great detail. A comparison between two perfect snapshots of old and young tissue would provide us with a very multi-faceted damage report. The aged tissue is riddled with "junk" molecules (by-products of normal metabolic functions) in and between cells, which do not dissipate, not even as the body heals and replenishes itself day in and day out. It would also show an accumulation of unwanted cells, and a depletion of necessary cells. All this damage reduces our tissue function, then our organ function, and eventually it kills us. How this damage accumulates, and how it leads to our demise, are matters of some dispute. But the bare facts of how our tissues alter over time already provide us with enough of a compass with which to chart the future course of medicine."