It is likely one of the sources of human spirituality.
You might be able to go with something more certain than, "likely", inasmuch as they sometimes drew us a diagram, or many, as such, depicting anthropomorphized cosmology. And because I'm in such a vague mood, it seems nearly sufficient to say that, given the realities behind notions of nothing ever going as planned, the facts of failure, frailty, and imperfection virtually require a comparative suggestion of enduring, unflawed success. Anthropomorphized perfection seems an inevitable logical outcome if one devises a complicated enough explanation to require containment within a singular and easily exchanged communication. By the time we get to existential questions themselves, the anthropomorphized polytheistic deities logically require a singular organizational principle, which thus emerges as a monotheistic godhead.
Imagine comparative perfection as an evolutionary symptom; all we really need is an underlying existential comparison, such as we might find implied in pretty much any explanation of kin selection.
But it's true, I think you could trade, "likely", for anything from, "evidently", to skipping it entirely in favor of something far more assured:
It is one of the fundamental sources of human spirituality.
Of course, I'm also considering the idea of pattern identification vaguely, and essentially presupposed; not necessarily self and other, as I haven't figured that one out, but something about distingusing this other from that other.