The first principle is that you must not fool yourself — and you are the easiest person to fool." R. P. Feynman, - David A. Sinclair

Over fifty years, Goldman estimated, the potential economic benefits of delayed aging would add up to more than $7 trillion in the United States alone. And that's a conservative estimate, based on modest improvements in the percentages of older people living without a disease or disability. Whatever the dollar figure, though, the benefits "would accrue rapidly," Goldman's team wrote, "and would extend to all future generations,"

In The Structure of Scientific Revolutions, Thomas Kuhn noted that scientific discovery is never complete; it goes through predictable stages of evolution. When a theory succeeds at explaining previously unexplainable observations about the world, it becomes a tool that scientists can use to discover even more.

Up until the second half of the twentieth century, it was generally accepted that organisms grow old and die “for the good of the species” — an idea that dates back to Aristotle, if not further.