The visible future is by any sensible measure nothing less than science fiction. Any given snapshot of that future is made up of countless trillions of ageless humans, sophisticated machine intelligences, and yet to be categorized hybrids of the two, spread throughout the solar system in palatial standards of living, and beginning to drift beyond to the nearby stars - a vast thistledown of intelligence and culture, a million times greater and more diverse than today's world, just beginning its explosion into the winds. These are the Inheritors, to borrow a term from an obscure work of science fiction.
The question for today is this: to what degree are we obligated by the Inheritors? They are yet to exist, but we know that we can bring them into being, and indeed seem to be headed in that direction: there is nothing especially controversial about a future cosmopolitan solar system, or the ability to defeat aging given a sufficiently long timescale to work on the necessary biotechnology. These technologies and research programs can be envisaged in some detail, and human ingenuity will achieve all of these goals in the fullness of time. (Though human nature being what it is research on the technologies of the future will be achieved painstakingly and ever so slowly on a shoestring budget, whilst the lion's share of the flow of expenditures in every society go to bread and circuses).
From a utilitarian perspective, one could argue that creating and perpetuating intelligences possessed of free will, freedom, and opportunity is the highest aspiration, the greatest end goal for human action - turning clay into sentience, as it were. Speeding any step towards the technologies necessary for the existence of the Inheritors (enhanced longevity, control of disease, strong artificial intelligence, low cost orbital lift systems, and so forth) will ultimately bring a benefit that is measured in millions of lives - even in increments of a day here, a day there. This is time lived in aggregate: deaths prevented, additional person-days lived well per day, days of suffering eliminated, and so forth.
Arguments for speed in longevity research based on saving lives in the future - bringing the advent of rejuvenation biotechnology one day closer will save at least 100,000 lives over the span of its introduction to the clinics, for example - are a narrow slice of broader arguments for speeding the development of the other foundation technologies of the Inheritors.
But are we obligated to the future? This seems to me to be an all or nothing question: are we obligated in the sense that we agree with Aubrey de Grey when he says that the ethical thing to do is to work hard on longevity technologies because it will give our descendants the choice of whether or not to use them - rather than lazing around and bequeathing them the same lack of choice that our ancestors had? If so, then shouldn't we also be obligated to the Inheritors as a result of much the same line of reasoning? And indeed, look beyond the Inheritors. The future of humanity, unless abruptly and unexpectedly halted, is to turn our future light cone into sentient matter. On that scale of time, space, culture, and intelligence the Inheritors are a tiny primordial instant. Are we obligated to the extent of the future that we cannot well envisage, only seeing that it must be vast beyond easy comprehension?
These are things to think about when you roll out of bed to face another day, and when you make the choice on your own plans and strategies for the years ahead.
The bottom line is that obligation is a choice. It is choice and freedom to choose that separates obligation from slavery: the difference between working because you feel that you should and working because you are compelled. The Inheritors, being nothing more than a plausible and probably inevitable vision at this point, cannot compel the present. To help speed the day of their existence, and to work on rejuvenation biotechnology and cryonics for a shot at seeing that era with our own eyes - these are choices. Weighty choices indeed, but freely made.