The Invention of Origins: VII. The Direction of a History

A history has a direction.

Events happen in time. Earlier states give rise to later states. Causes precede their consequences. Once something has happened, it belongs to the past.

But a history does not necessarily have a destination.

This distinction is easy to lose when we look backwards.

Suppose a particular sequence of events eventually produces something new. We can trace the sequence from its earlier conditions to its later outcome. Because we know where it ends, the sequence can look directional in a stronger sense: it can look as though it was moving towards the outcome.

But temporal direction is not teleological direction.

A river flows downhill, but it does not flow towards the sea because the sea is its purpose. Evolutionary change occurs through processes that have temporal direction, but this does not mean that evolution is moving towards whatever forms eventually emerge.

The distinction becomes particularly important when we reconstruct long histories.

Looking backwards, we see actual events. The possibilities that disappeared leave little trace. A history therefore appears narrower in retrospect than it was while unfolding.

At an earlier point, several futures may have been possible.

Only one became actual.

Once we know which one, that future can make the preceding history appear more constrained than it really was.

We see the path that happened.

We do not see, with equal vividness, the paths that didn't.

This is one source of historical asymmetry. The future was once possibility; the past is now actuality. Retrospective explanation therefore begins with a world in which the alternatives have already vanished.

And so a branching history can look like a line.

The danger is to mistake the line for a trajectory.

A trajectory implies more than sequence. It suggests direction towards a destination.

But the history of life, for example, is better understood as branching, contingent and continuously transformed. Humans are one outcome among innumerable outcomes. We can trace the particular history that produced us without turning that history into a journey whose destination was humanity.

Perhaps the same applies to origins.

An origin is often the point at which we decide that a particular direction of history began.

But the direction may have been supplied retrospectively by the outcome.

The past did not know where it was going.

And this may be the deepest reason to be cautious with teleological language. It can turn the asymmetry of time into a purpose of time.

Time gives us an irreversible sequence of events.

We give that sequence a destination.

The first may belong to the world.

The second may belong to us.