There are many theories about evolution. Charles Darwin's is perhaps the most
famous, but the concept had been around long before him. Meher Baba wrote an exhaustive detailed account of His perspective on evolution and involution titled, "God Speaks; The Theme Of Creation And It's Purpose"
Here's a decent (though extremely limited) thumbnail retelling of what Baba says about evolution in "God Speaks" from a website dedicated to Him:
http://www.ambppct.org/meherbaba/meher-baba-life-4.php
"Meher Baba said that he had come not to teach but to awaken, nonetheless his various messages and books, particularly God Speaks and the Discourses, present a definite and coherent cosmology. God, as he explained, is the sole Reality, and the created universe exists only in dream or imagination. The dream of creation originated in the Whim of God to know Himself. This precipitated an evolution of consciousness in which the “drop-soul” (or jeevatma), identifying with innumerable physical forms and thereby growing in experience, progressed from stone and metal through varied species of the vegetable, worm, fish, bird, and animal kingdoms.
In human form, which is the terminus of evolution, consciousness is fully developed, but now the soul experiences the accumulated impressions of evolution rather than its own, native God-state. This ignorance necessitates further births and deaths in human form in the round of reincarnation. Still impelled by the God’s original Whim to know Himself, at length the soul turns inward and embarks upon what Meher Baba called the process of involution. This involutionary journey leads out of the gross or physical and on through the subtle and mental spheres (that is, the spheres of energy and mind), spanning seven planes of higher consciousness. The spiritual path culminates on the seventh plane with the experience of Divine Union or God-Realization, wherein the soul acquires direct and incontrovertible Knowledge of itself as God, the sole Being and infinite Reality."
I don't know if you're asking whether evolution is justified, or whether you mean "Has evolution been proven?"
My answer to both would have to be that the truth doesn't have to be justified, it is what it is no matter who believes or disbelieves it.
What the truth is about evolution in particular has yet to be proven or disproven (if it ever can be conclusively.)