(this is speculative, FWIW)
There are a lot of Bahá’í Writings, applying to a lot of different contexts, and many aren’t translated yet. But I’ve been puzzling over two quotes. The first is:
Know thou that every fixed star hath its own planets, and every planet its own creatures, whose number no man can compute. (Gleanings, LXXXII)
This makes sense to me — how could a universe so vast (and probably not the only one) not have life everywhere? And the concept of social progress with the Bahá’í concept of Progressive Revelation — that we are evolving from family unity, to tribal, to national, and now we need world unity — surely implies interplanetary unity somewhere down the road? And besides, there’s Star Trek 😉
The other quote is:
Having created the world and all that liveth and moveth therein, He, through the direct operation of His unconstrained and sovereign Will, chose to confer upon man the unique distinction and capacity to know Him and to love Him—a capacity that must needs be regarded as the generating impulse and the primary purpose underlying the whole of creation.… Upon the inmost reality of each and every created thing He hath shed the light of one of His names, and made it a recipient of the glory of one of His attributes. Upon the reality of man, however, He hath focused the radiance of all of His names and attributes, and made it a mirror of His own Self. Alone of all created things man hath been singled out for so great a favor, so enduring a bounty. (Gleanings, XXVII)
This too makes sense — this physical world is a nurturing home for humanity, and the definition of “mankind” or “humanity” is often cited as “fully reflecting all of the attributes of God”, not just some of them like the mineral, plant, and animal Kingdoms.
But look at that second quote closer: it says “man has the unique distinction and capacity to know Him”. Surely the Klingons can also know God? And we’re not admitting a pantheon of gods, there is just One God for both Klingons and Earthlings.
So if I bring those 2 quotes together, it seems to me in a Star Trek future, we would have to use the words “human” or “mankind” to also include all the different intelligent species in the universe, and they would have human souls, neither Klingon souls nor Earthling-specific souls.
This might be quite a shift in our thought. There’s probably a reason the distances between stars is so large, related to our capabilities now.
Orson Scott Card explores this in Ender’s Game, where we face the guilt of wiping out an entire race of beings before really knowing them, if I remember it correctly.