0:00:07.114,0:00:09.163
Nicholas Steno is rarely heard of

0:00:09.163,0:00:11.252
outside Intro to Geology,

0:00:11.252,0:00:13.999
but anyone hoping to understand life on Earth

0:00:13.999,0:00:17.174
should see how Steno expanded and connected

0:00:17.174,0:00:18.675
those very concepts:

0:00:18.675,0:00:21.391
Earth, life, and understanding.

0:00:21.391,0:00:25.226
Born Niels Stensen in 1638 Denmark,

0:00:25.226,0:00:26.813
son of a goldsmith,

0:00:26.813,0:00:28.139
he was a sickly kid

0:00:28.139,0:00:30.642
whose school chums died of plague.

0:00:30.642,0:00:32.559
He survived to cut up corpses

0:00:32.559,0:00:33.726
as an anatomist,

0:00:33.726,0:00:36.357
studying organs shared across species.

0:00:36.357,0:00:38.388
He found a duct in animal skulls

0:00:38.388,0:00:40.227
that sends saliva to the mouth.

0:00:40.227,0:00:41.728
He refuted Descartes' idea

0:00:41.728,0:00:43.862
that only humans had a pineal gland,

0:00:43.862,0:00:46.113
proving it wasn't the seat of the soul,

0:00:46.113,0:00:48.558
arguably, the debut of neuroscience.

0:00:48.558,0:00:51.949
Most remarkable for the time was his method.

0:00:51.949,0:00:54.006
Steno never let ancient texts,

0:00:54.006,0:00:55.708
Aristotelian metaphysics,

0:00:55.708,0:00:57.396
or Cartesian deductions

0:00:57.396,0:01:00.927
overrule empirical, experimental evidence.

0:01:00.927,0:01:05.131
His vision, uncluttered by speculation or rationalization,

0:01:05.131,0:01:06.184
went deep.

0:01:06.184,0:01:07.673
Steno had seen how gall stones

0:01:07.673,0:01:10.426
form in wet organs by accretion.

0:01:10.426,0:01:11.768
They obeyed molding principles

0:01:11.768,0:01:13.556
he knew from the goldsmith trade,

0:01:13.556,0:01:16.474
rules useful across disciplines for understanding solids

0:01:16.474,0:01:18.771
by their structural relationships.

0:01:18.771,0:01:20.310
Later, the Grand Duke of Tuscany

0:01:20.310,0:01:21.977
had him dissect a shark.

0:01:21.977,0:01:23.890
Its teeth resembled tongue stones,

0:01:23.890,0:01:26.393
odd rocks seen inside other rocks

0:01:26.393,0:01:28.979
in Malta and the mountains near Florence.

0:01:28.979,0:01:31.203
Pliny the Elder, old Roman naturalist,

0:01:31.203,0:01:33.530
said these fell from the sky.

0:01:33.530,0:01:36.312
In the Dark Ages, folks said they were snake tongues,

0:01:36.312,0:01:38.254
petrified by Saint Paul.

0:01:38.254,0:01:40.828
Stenos saw that tongue stones were shark teeth

0:01:40.828,0:01:42.393
and vice versa,

0:01:42.393,0:01:45.003
with the same signs of structural growth.

0:01:45.003,0:01:47.757
Figuring similar things are made in similar ways,

0:01:47.757,0:01:49.396
he argued the ancient teeth

0:01:49.396,0:01:50.724
came from ancient sharks

0:01:50.724,0:01:53.679
in waters that formed rock around the teeth

0:01:53.679,0:01:55.605
and became mountains.

0:01:55.605,0:01:58.637
Rock layers were once layers of watery sediment,

0:01:58.637,0:02:00.280
which would lay out horizontally,

0:02:00.280,0:02:01.390
one atop another,

0:02:01.390,0:02:03.105
oldest up to newest.

0:02:03.105,0:02:04.726
If layers were deformed,

0:02:04.726,0:02:05.200
tilted,

0:02:05.200,0:02:06.026
cut by a fault,

0:02:06.026,0:02:07.146
or a canyon,

0:02:07.146,0:02:09.611
that change came after the layer formed.

0:02:09.611,0:02:10.779
Sounds simple today;

0:02:10.779,9:59:59.000
back then, revolutionary.

9:59:59.000,9:59:59.000
He'd invented stratigraphy

9:59:59.000,9:59:59.000
and laid geology's ground work.

9:59:59.000,9:59:59.000
By finding one origin for shark teeth from two eras

9:59:59.000,9:59:59.000
by stating natural laws ruling the present

9:59:59.000,9:59:59.000
also ruled the past,

9:59:59.000,9:59:59.000
Steno planted seeds for uniformitarianism,

9:59:59.000,9:59:59.000
the idea that the past was shaped by processes

9:59:59.000,9:59:59.000
observable today.

9:59:59.000,9:59:59.000
In the 18th and 19th centuries,

9:59:59.000,9:59:59.000
English uniformitarian geologists,

9:59:59.000,9:59:59.000
James Hutton and Charles Lyell,

9:59:59.000,9:59:59.000
studied current, very slow rates

9:59:59.000,9:59:59.000
of erosion and sentimentation

9:59:59.000,9:59:59.000
and realized the Earth had to be way older

9:59:59.000,9:59:59.000
than the biblical guestimate, 6000 years.

9:59:59.000,9:59:59.000
Out of their work came the rock cycle,

9:59:59.000,9:59:59.000
which combined with plate tectonics

9:59:59.000,9:59:59.000
in the mid-twentieth century

9:59:59.000,9:59:59.000
to give us the great molten-crusting, quaking,

9:59:59.000,9:59:59.000
all-encircling theory of the Earth,

9:59:59.000,9:59:59.000
from a gall stone to a 4.5 billion year old planet.

9:59:59.000,9:59:59.000
Now think bigger,

9:59:59.000,9:59:59.000
take it to biology.

9:59:59.000,9:59:59.000
Say you see shark teeth in one layer

9:59:59.000,9:59:59.000
and a fossil of an organism

9:59:59.000,9:59:59.000
you've never seen under that.

9:59:59.000,9:59:59.000
The deeper fossil's older, yes?

9:59:59.000,9:59:59.000
You now have evidence

9:59:59.000,9:59:59.000
of the origin and extinction of species over time.

9:59:59.000,9:59:59.000
Get uniformitarian.

9:59:59.000,9:59:59.000
Maybe a process still active today

9:59:59.000,9:59:59.000
caused changes not just in rocks, but in life.

9:59:59.000,9:59:59.000
It might also explain similarities and differences

9:59:59.000,9:59:59.000
between species

9:59:59.000,9:59:59.000
found by anatomists like Steno.

9:59:59.000,9:59:59.000
It's a lot to ponder,

9:59:59.000,9:59:59.000
but Charles Darwin had the time

9:59:59.000,9:59:59.000
on a long trip to the Galapagos,

9:59:59.000,9:59:59.000
reading a copy of his friend

9:59:59.000,9:59:59.000
Charles Lyell's "Principles of Geology,"

9:59:59.000,9:59:59.000
which Steno sort of founded.

9:59:59.000,9:59:59.000
Sometimes giants stand on the shoulders

9:59:59.000,9:59:59.000
of curious little people.

9:59:59.000,9:59:59.000
Nicholas Steno helped evolve evolution,

9:59:59.000,9:59:59.000
broke ground for geology,

9:59:59.000,9:59:59.000
and showed how unbiased, empirical observation

9:59:59.000,9:59:59.000
can cut across intellectual borders

9:59:59.000,9:59:59.000
to deepen our perspective.

9:59:59.000,9:59:59.000
His finest accomplishment, though,

9:59:59.000,9:59:59.000
may be his maxim,

9:59:59.000,9:59:59.000
casting the search for truth

9:59:59.000,9:59:59.000
beyond our senses and our current understanding

9:59:59.000,9:59:59.000
as the pursuit of the beauty

9:59:59.000,9:59:59.000
of the as-yet unknown.

9:59:59.000,9:59:59.000
Beautiful is what we see,

9:59:59.000,9:59:59.000
more beautiful is what we know,

9:59:59.000,9:59:59.000
most beautiful, by far, is what we don't.