Efforts to narrow the rift apparent between, on the one hand, science, and on the other, religion (or, most especially, revelation-based theistic faiths) often run through the territory of creative interpretation of one discipline or the other. There are, naturally, two directions in which this prescription flows: one, the assertion that the scriptural account is literally accurate, and that science is accurate only insofar as it may be read to support the scriptural narrative; and two, the assertion that scientific accounts alone are accurate and that whatever is reported in scripture is an allegory of the scientifically discoverable occurrence, or is otherwise subject to a scientific explanation. For example, as to the first method, geographic markers usually taken to indicate slow and sporadic flooding events may be proposed by scriptural literalists as evidence of a single world-wide flood, an event remarked upon in religious traditions from many parts of the world. As to the second method, certain of those same signs might be staked as logical explanations as to why the scripture-writers believed a localized flood to be worldwide, or were given to a metaphor of such a flood (then argued to have never been intended for literal interpretation) thus preserving some measure of validity to that scripture.
Falling within the latter vein,of late, are particular series of parables in Hindu scripture which tell of Vishnu--the ultimate expression of the divine essence, the meta entity within which our whole Universe is wrapped--revealing himself to man in particular forms, known as avataras, arriving in a particular progression. Those forms, it is noted by followers, were those particularly appropriate to the situation in which he appeared (appearing, for example, as a fish to warn of the coming flood, and as a turtle to assist in salvaging what remained after the flood). But more than that, it is posited, a remarkable correlation is to be found between the mythical recounting of the progression of those forms and what is now understood by scientific examination to be the order through which evolution by natural selection has brought to pass the variety of life on Earth.
The ten incarnations accepted by most authorities on the Hindu scripture are:
. Matsya . -- which begins as a very tiny fish, but grows to be a great fish, filling the ocean
.. Kurma .. -- a tortoise
... Varaha ... -- a boar
.... Narsimha .... -- a "hybrid" half-man and half-lion
..... Vamana ...... -- a Dwarf
...... Parasurama ...... -- Rama, the hero with an axe
....... Rama ....... -- the princely hero of the Ramayana epic
........ Krishna ........ -- the divine teacher of the Gita
......... Buddha ......... -- the enlightened founder of Buddhism
.......... Kalki .......... -- which is yet to come....
We begin, then, with Matsya. Matsya comes to warn the faithful Dravidian king Manu that a flood is coming which will drown all life on Earth. When he first appears, he is the tiniest of minnows, whom Manu is able to fit in a jar; but soon Matsya outgrows the jar, and then the tub in which he is next placed, and then even the river, and finally the whole ocean. Then the fish reveals itself to be Vishnu, and instructs the king of the coming flood, and of the need to save all manner of medicinal herbs and other valuable seeds. It is noteworthy that the flood thus described is not claimed to have come from Matsya (or Vishnu), and not to be a punishment directed against man; it is simply a natural occurrence which man is being warned of. Representations of Matsya tend to depict a four-armed upper torso of a man protruding from the mouth of a great fish, but the myth makes it clear that Matsya was the fish itself. And in support of the evolutionary biological argument, it is claimed that Matsya's piscine nature represents the oceanic origin of all life on Earth.
Kurma, the huge tortoise, is the form Vishnu takes after the flood has passed, in some accounts it arrives right afterwards to assist in the rebuilding of civilization, but in most it comes in a different era to deal with a different ocean; as an amphibious animal it is capable of retrieving the gods' elixir of immortality which had been carried by the flood to the ocean's deepest reaches. Restoring it to the demigods of the day, it enables them to defeat various evil demons who had stripped them of their powers. Kurma is claimed, then, to represent the transition from fish to reptiles (though a true amphibian in between would have been a better tell of this). Not long after, the demon Hiranyaksha appears, steals the Vedas, and plunges the Earth itself to the depths of the 'cosmic ocean.' Vishnu reappears in his third avatara, Varaha, the giant Boar. After a thousand-year battle, Vahara prevails and carries the Earth up from the depths between his tusks, in order to return it to its rightful place in our Universe. The boar, then, is claimed to represent the next transition, from reptile to mammal.
Narsimha, the "half-man, half-lion," to my mind, brings forth the image of an animal with some feature which would make one think of a man, and some which would make one think of a lion: the baboon. There are many species of baboon, and amongst them, the Guinea Baboon is known in particular for the lion-like mane of the adult male. It is observed to walk at times on all fours, and other times to stand and take a few steps on its hind legs, and to manipulate things in a markedly human-like fashion with its dexterous primate hands. This is, it must be confessed, a bit of a stretch to accommodate the scriptural narrative into an evolutionary narrative, but at the same time there is no actual half-man half-lion in existence to work into it scientifically. In the myth, Vishnu appears in this 'half-man, half-lion' form to defeat Hiranyakashipu, a demon who had been granted immunity from enemies when indoors and out, when on the ground or in the sky, during the day and in the night, and from both manufactured weapons and living hands. Narimha defeated Hiranyakashipu by seizing him in a doorway (neither inside nor out), at twilight (neither day nor night), holding him on his thigh (not on the ground, nor in the sky), and disemboweling him with his lion-like nails (neither living hands, nor man-made weapons).
That last beast is the last 'beast,' all the rest of Vishnu's incarnations being recognizably human. As to Vamana, the "dwarf," this raises the image of "Lucy," the famously diminutive specimen of species Australopithecus afarensis, a short-statured link in the chain of human evolution. The remainder of the incarnations are human, though arguably representative of progressive stages of human evolution, or, alternately, of the evolution of human civilizations, if not both. Parasurama, Rama, and Krishna are most easily analogized as simply being humans advancing across different levels of civilization and enlightenment. Parasurama, notably, is 'Rama with an ax,' and is oft depicted as swarthed in a beardly beard, conceivably, then, a hairier 'primitive man' version of Rama. And though the inclusion of the Buddha amongst these incarnations is claimed by some as cynically indicating some co-option of religious symbolism by the Hindu majority, it confesses at the same time a universality of recognition of the Buddha as a force for goodness and instruction toward right conduct. But observe as well that in a smaller number of traditions, a brother of Krishna named Balarama, described as well as an enlightened teacher, is included in place of Buddha; this view is most often criticized from the view that Krishna and Balarama lived at the same time, while all other avatara live in distinct and nonoverlapping eras.
And at last there is Kalki, riding a white horse, bringing with him the immolation of our Universe entire, in a blinding white light -- stepping out of the evolutionary fold, this is claimed by some to presage the physics dictating the end of our Universe itself, either by a Big Crunch (possibly leading to a new cycle), or heat death, or some comparably cataclysmic coming.
And through all this it must be remembered that there are precious few 'fundamentalist' or 'literalist' Hindus, who would claim all the tales told above to be literal truths instead of symbolic depictions, making it more palatable to assume that stages of evolution by natural selection were indeed being showcases here. Indeed, some nineteenth century Hindu thinkers thought Charles Darwin had himself taken an unacknowledged cue from Hinduism, an error fueled by J. B. S. Haldane, an English scientist of the same field, who connected the ideas after the fact. But that claim would have been inestimably strengthened by more and more explicitly intermediary incarnations invoking animals which would fill fossil record gaps. Perhaps if Vishnu had earlier appeared as a great crustacean? Or an improbably large bacterium? But still, were one looking for a revelational theistic faith whose scripture was most immediately analogisable to the scientific evidence available, the evolutionary progression of the avatara of Vishu offers as qualified a candidate as any.