The modern movements of transhumanism and support for longevity science have deep roots: you can find early expressions of the ideas of human enhancement and overcoming natural limits on our biology in a range of writings from past centuries. These ideas became more commonplace and more complex over time as the prospects for technology caught up with our desires:
Immanuel Kant (1724-1804) was an 18th century philosopher, one of the earliest philosophers belonging to the enlightenment tradition, and often considered the father of German Idealism. Kant is remembered today more for his moral philosophy than his contributions to metaphysics and epistemology (Rohlf 2010). His contributions to the field of life-extension, however, remain almost completely unexplored, despite the fact that certain claims made in his Theory of Ethics arguably qualify him as a historical antecedent of the contemporary social movement and academic discipline of life-extension.
Marquis du Condorcet (1743-1794), another historical antecedent the modern longevity movement, appears to have originated the "idea of progress" in the context of the enlightenment, which became an ideological cornerstone of the enlightenment tradition. In Sketch for a Historical Picture of the Progress of the Human Mind, Condorcet not only conceives of the idea of progress in perhaps the first form it would take within the enlightenment tradition, but also explicates its link to indefinite life-extension, which was not an existing movement or academic discipline at the time of his writing:
"Would it be absurd now to suppose that the improvement of the human race should be regarded as capable of unlimited progress? That a time will come when death would result only from extraordinary accidents or the more and more gradual wearing out of vitality, and that, finally, the duration of the average interval between birth and wearing out has itself no specific limit whatsoever? No doubt man will not become immortal, but cannot the span constantly increase between the moment he begins to live and the time when naturally, without illness or accident, he finds life a burden?"
It is this very notion of infinite progress towards endlessly-perfectible states, carried forward after Condorcet by Kant and other members of the enlightenment tradition, that also underlies Kant's own ties to the contemporary field of life-extension. Kant's claim, made in his Theory of Ethics, that to retain morality we must have comprehensively unending lives - that is, we must never, ever die - I will argue qualifies him as a historical antecedent of the contemporary life-extension movement.