If it is indeed the will of Nature to eventually create the unity of humanity in one overarching governing aggregate, then, so the argument goes, why not just follow the path of least resistance, bring about the physical unification, and let the psychological unity follow along afterwards? The issue here is that the process of Nature can be slow, and extremely messy or violent when no other methods seem to be working, and thus, failing to work towards a consciously evolved solution may doom humanity to considerable additional pain and suffering as the process works itself out.
Sri Aurobindo observes: “Well then, it may be said, let us trust to this inevitable will in Nature and let us follow out her method of operation. Let us create anyhow this framework, any framework of the aggregate; for she knows already the complete form she intends and she will work it out eventually in her own time; by the power of the idea and our will to reaise it, by help of strong force of circumstances, by pressure of all kinds, by physical force ven, if need be, since that too seems still to be a part of her necessary machinery, let us create it. Let us have the body; the soul will grow in the body. And we need not mind if the bodily formation is artificial with at first a small or no conscious psychological reality to vivify it. That will begin to form itself as soon as the body has been formed.”
“As a national ego formed which identified itself with the geographical body of the nation and developed in it the psychological instinct of national unity and the need of its satisfaction, so a collective human ego will develop in the international body and will evolve in it the psychological instinct of human unity and the need of its satisfaction. That will be the guarantee of duration. And that possibly is how the thing will happen, man being what he is; indeed if we cannot do better, it will so happen, since happen somehow it must, whether in the worse way or the better.”
Sri Aurobindo, The Ideal of Human Unity, Part Two, Chapter 33, Internationalism and Human Unity, pp. 287-288