It was most memorably formulated by Charles Darwin in the 19th centruty.

Part of the theory focuses on the tendency on genes to mutate.

When a frog, or a microbe, or a giraffe has a gene mutation,

it usually means that they'll be unsuited to their environment and will simply die.

But very occasionally, just by chance, the mutation gives them an advantage and makes them more successful.

The mutation is passed on to their descendants, who will have the same advantage as their parents,

and their result in success will spread it ever further down the generations.

But the key thing about gene mutation is that it takes time-- a lot of it.

It took us around 3,900 million years to go from the first cells to homo sapiens.

So the one thing we can be pretty sure about is that genetic mutation will not be a significant feature

of the human world now.

However, there's a second, equally interesting bit to Darwin's theory of evolution,

which focuses on what gets called "adaptation to the environment."

Darwin pointed out that when an environment changes,

a characteristic can suddenly shift from being an advantage to a disadvantage, and vice versa.

In 1811, a famous survey of moths around the bordering town of Manchester

recorded no melanic or black-winged moths.

37 years later, in 1848, another survey discovered huge numbers of these creatures,

and far fewer white-winged moths.

Darwin's explanation was simple: Manchester's rise as a major industrial city

meant that huge quantities of soot had entered the atmosphere and darkened tree trunks.

Thereafter, light-winged moths became highly conspicuous to their main predators, birds,

while the dark-winged ones were effectively camouflaged.

Darwin concluded that changes to the environment

can dramatically alter which members of a species will thrive within it.

This happens in the human world, where it doesn't affect reproductive potential,

but does change the social hierarchy.

Consider, for instance, the classic example of our age.

The rise of the nerd: being short sighted, timid, having poor muscular development,

being obsessed with complex, abstract processes, and being short on charisma and social skills

used to be a recipe for an unsuccessful life.

That's because, for most of history, making your way in the world was hugely dependent on physical strength,

and strong practical links to a family group.

The weakling, the loner, and the introvert were in very disadvantageous positions.

Then, in the last quarter of the 20th century, the tech industry created an environment

in which nerd-characteristics turned out to be highly advantageous.

Human beings are not themselves now, evolving or too slowly to matter.

But our environment is changing very fast,

and this has hugely privileged certain traits while penalizing others.

A key dynamic of evolution, adaptation to the environment, is still very much around,

even though gene mutation may not be a notable factor.

Some of us are like the black moths of industrial Manchester,

ideally suited to the new world,

which rewards massive intellect, self-discipline, and rationality.

Others, many, many of us, are like white moths in a newly sooty world.

We find it hard not to eat too much, to distinguish real threats from baseless anxieties,

to spend all day in an office in front of a computer, to look at porn in moderation, to be monogamous,

and to defer gratification for years

while we collaborate on large projects inside the glass towers of corporations.

We should feel compassion for ourselves when we don't quite fit our times.

Our biology has saddled us with a range of cognitive habits which were sensible when they evolved--

habits around sugar, sex, power, anxiety, and excitement--

with which really hamper our effectiveness in the modern world.

An understanding of the theory of evolution should move us to sympathy

for why we do some of the deeply counterproductive things we do.

When he first wrote about evolution, Charles Darwin was accused of demeaning human nature;

cartoonists loved to draw him as an ape.

But Darwin was being deeply kind and helpful to us humans.

He was reminding us that we carry with us a lot of baggage, which we don't now need,

but which we can't get rid of very fast.

Modern life has required things of us which are really very hard for us pull off.

We're saddled with so many inconvenient but maddeningly deep-rooted tendencies,

which is yet another reason why we constantly need to be a little more forgiving of other people

and of ourselves.