And, in this case, science could learn an important lesson from the literati — who love contingency for the same basic reason that scientists tend to… - Stephen Jay Gould

Life is a ramifying bush with millions of branches, not a ladder. Darwinism is a theory of local adaptation to changing environments, not a tale of inevitable progress. “After long reflection,” Darwin wrote, “I cannot avoid the conviction that no innate tendency to progressive development exists.”
Jastrow might argue that he is only considering the single pathway through the immense labyrinth of life’s bush that happened to lead to us. Even here I might reply that while we have a personal motive for special interest in (and affection for) this particular pathway, we have no right to regard it (or any other) as the essential direction of life. The pathways leading to aardvarks, anchovies, or artichokes are just as long, intricate, and biologically informative.

Consider one of the standard "laments" or "stories of wonder" in conventional tales of natural history: the mayfly that lives but a single day (a sadness even recorded in the technical name for this biological group - Ephemoptera). Yes, the adult fly may enjoy only a moment in the sun, but we should honor the entire life cycle and recognize that the larvae, or juvenile stages, live and develop for months. Larvae are not mere preparations for a brief adulthood. We might better read the entire life cycle as a division of labor, with larvae as feeding and growing stages, and the adult as a short-lived reproductive machine. In this sense, we could well view the adult fly's day as the larva's clever and transient device for making a new generation of truly fundamental feeders.

We have become, by the power of a glorious evolutionary accident called intelligence, the stewards of life's continuity on earth. We did not ask for this role, but we cannot abjure it. We may not be suited to it, but here we are.