Every man* has his own temperament, value system, -- and so on -- that reason alone begets wildly different what-should-be-dones. That is, unless the achievement of a narrow aim would benefit the many---and therefore all those different reason machines come together to collectively strive towards some end---then we have all sorts of different, many times conflicting, what-should-be-dones (politics is a prime example here).
Perhaps then an authority should be appointed?; someone or some group whose sole purpose is to reason all day and all night, until they come up with a what-should-be-done that benefits their constituency (of course, this assumes they didn't ascend by force, coercion, or some other deviousness).
But now, we get into this dreadful stalemate: the more constituents there are, the more the means and the ends have to be tailored to them, and the more the whole venture becomes watered down, in order to suit some muddied "average." Or perhaps the authority decides to "draw a line in the ground," to create some abstract "core" of acceptable means and ends (as well as people to enlist), and shun out the rest---in order to maintain some semblance of identity and individualism.
Yet, now we have two very inefficient differentiations. On one hand, we have the all-inclusive reasoning-body, that is so held back by trying to please all, that it pleases none. On the other hand, we have the some-exclusive reasoning-body, that -- fortunately, or unfortunately, depending on one's own reasoning -- shuts out the "others," and does nothing to support the advancement of their ends (many times, quite the opposite).
I think it is self-evident that both are inefficient towards the coordination of all humanity. So are there any alternatives?
Perhaps we could simply do away with collective coordination -- or atleast some less rigid approach?
What about some type of individualism?; where each man* decides his own fate. Therein, each member is responsible for his own fate, and therefore---collectively---the fate of all man? Each soul going in his own direction, serving his interests foremost, and pushing the fate of humanity, in his own image, little by little -- like some plant, slowly rooting itself into the most impenetrable places, and overcoming the, otherwise apparent, impossible odds.
On a local level, humanity is ever unsustainable, "booming-and-busting," but on the world level we have survived, and will continue until we lose our survival instincts (impossible, collectively). Each member of the human race will do what he must to survive and improve his own circumstances, even if it leaves others worse off; then, those worse-offs must now improve their circumstances further, and strive for a better life. In the end, each man guarantees the survival (but not thrival) of the human race, by the virtue of his selfishness.
*Are we still doing the "man" is not synonymous with "human" fad? It's more of a stylistic choice, rather than an "only men can use reason." I.e, it flows better than "hu-man."