The relationship that this work had to aging was then picked up by many people worldwide, who pursued the study of cultured human cells – and other animal cells, as well – and in respect to understanding more about the biology of aging. It should be understood, if it isn't already, that folks working in the field of the biology of aging in the '60s were considered to be outside of the realm of the mainstream of science. The mainstream of science in general felt that studying aging was a total waste of time, that it would yield no significant results. With some exceptions – notable exceptions – it was ignored, at least in respect to trying to understand the fundamental biology of aging, and it's important for me to make some kind of definition of these terms at this point, because they're significant in respect to the events that occurred subsequently.

There is a very important difference between the four... four aspects of the finitude of life. The four are: death, age-associated diseases, aging and the determinance of longevity. That concept didn't develop in my mind until recent years, but it does have a bearing on the earlier events.

 It soon became apparent to me that a belief – not only later held by me, and certainly not initiated in my mind – was a correct interpretation of the biology of aging, and that is that age associated diseases, in themselves, studied – and even resolved – would not provide any insights into the fundamental biology of aging. And that belief, held by me still to this day, is based on the following facts. If... when the resolution of childhood diseases occurred – namely things like Wilms' Tumour, iron deficiency anemia, diseases and deaths caused by polio or other viruses or microorganisms – when those occurred during the 20^th century, none of them revealed any insights into the fundamental biology of childhood development. It is... that argument pertains to the biology of aging. The resolution of any age-associated disease – namely the leading causes of death: cardiovascular disease, stroke and cancer – will not yield any information on the fundamental biology of aging. People who recover from those ailments continue to age. What probably will happen is that if and when those diseases are completely resolved, individuals will continue to age, but there will be a limit. The limit will be a life expectation increase from the present average life expectancy of about 79 or 80 years in developed countries to about 92 years. That will be the maximum.

Many people are surprised when you quote the actual mathematics of the situation and argue about the outcome of resolving major causes of diseases, and this can be determined mathematically with reasonable precision. If you resolve causes of death attributable to cancer, today, the additional life expectation that will occur is about two years. A value that most people would be surprised to hear, many people who I've quizzed on this will give you double figures of some sort. Likewise, the leading cause of death – cardiovascular disease and stroke, lumped together – will yield about 3.2 or so years of life expectation. At virtually every age that's true of cancer, in respect to the number I quoted earlier, and one then, by doing this kind of math, is led to the conclusion that the total increase that will occur yields a value of about 92 years. Now, of course, you can't resolve what we call stochastic events – that is, accidents, murder, suicide, wars, etc. – but from a statistical standpoint, and because most people do not die from those causes, it's a trivial number, which we probably could never exclude. The cause of death, then, will be – probably, because we really don't know – the loss of physiological capacity in some major organ: the heart, lung, kidneys, liver, etc. So we'll have to invent a whole new vocabulary to put on our death certificates.