That chain of contingency — the specific conditions that had to be met, the specific choices and accidents that led to the discovery — makes the White Sands footprints both extraordinarily precious and appropriately humbling.

We know this much about these people: where they walked, roughly when they walked, that they walked with children, that they shared their landscape with animals that no longer exist.

We know that they were here during a period when the standard model of American prehistory said they could not have been.

We know almost nothing else.

The footprints are a reminder of what is always true about archaeological evidence at this depth of time: the record is fragmentary, the silences are enormous, and what we know is always less than what happened.

The people of White Sands had lives as complex and full and particular as any human lives.