Frost is presenting an antimyth in which origin, destination, and return are undermined by a nonprogressive development. And the hero has only illusory choice. This psychological representation of the developmental principle of divergence strikes to the core of Darwinian theory. Species are made and survive when individuals diverge from others in a branching scheme, as the roads diverge for the speaker. The process of selection implies an unretracing process of change through which individual kinds are permanently altered by experience. Though the problem of making a choice at a crossroads is almost a commonplace, the drama of the poem conveys a larger mythology by including evolutionary metaphors and suggesting the passage of eons.
[T]he large moral meaning which "The Road Not Taken" seems to endorse—go, as I did, your own way, take the road less traveled by, and it will make "all the difference"—does not maintain itself when the poem is looked at more carefully. Then one notices how insistent is the speaker on admitting, at the time of his choice, that the two roads were in appearance "really about the same," that they "equally lay / In leaves no step had trodden black," and that choosing one rather than the other was a matter of impulse, impossible to speak about any more clearly than to say that the road taken had "perhaps the better claim." But in the final stanza, as the tense changes to future, we hear a different story, one that will be told "with a sigh" and "ages and ages hence." At that imagined time and unspecified place, the voice will have nobly simplified and exalted the whole impulsive matter into a deliberate one of taking the "less traveled" road:
Two roads diverged in a wood, and I—I took the one less traveled by,And that has made all the difference.