WEBVTT 00:00:07.114 --> 00:00:09.163 Nicholas Steno is rarely heard of 00:00:09.163 --> 00:00:11.252 outside Intro to Geology, 00:00:11.252 --> 00:00:13.999 but anyone hoping to understand life on Earth 00:00:13.999 --> 00:00:17.174 should see how Steno expanded and connected 00:00:17.174 --> 00:00:18.675 those very concepts: 00:00:18.675 --> 00:00:21.391 Earth, life, and understanding. 00:00:21.391 --> 00:00:25.226 Born Niels Stensen in 1638 Denmark, 00:00:25.226 --> 00:00:26.813 son of a goldsmith, 00:00:26.813 --> 00:00:28.139 he was a sickly kid 00:00:28.139 --> 00:00:30.642 whose school chums died of plague. 00:00:30.642 --> 00:00:32.559 He survived to cut up corpses 00:00:32.559 --> 00:00:33.726 as an anatomist, 00:00:33.726 --> 00:00:36.357 studying organs shared across species. 00:00:36.357 --> 00:00:38.388 He found a duct in animal skulls 00:00:38.388 --> 00:00:40.227 that sends saliva to the mouth. 00:00:40.227 --> 00:00:41.728 He refuted Descartes' idea 00:00:41.728 --> 00:00:43.862 that only humans had a pineal gland, 00:00:43.862 --> 00:00:46.113 proving it wasn't the seat of the soul, 00:00:46.113 --> 00:00:48.558 arguably, the debut of neuroscience. 00:00:48.558 --> 00:00:51.949 Most remarkable for the time was his method. 00:00:51.949 --> 00:00:54.006 Steno never let ancient texts, 00:00:54.006 --> 00:00:55.708 Aristotelian metaphysics, 00:00:55.708 --> 00:00:57.396 or Cartesian deductions 00:00:57.396 --> 00:01:00.927 overrule empirical, experimental evidence. 00:01:00.927 --> 00:01:05.131 His vision, uncluttered by speculation or rationalization, 00:01:05.131 --> 00:01:06.184 went deep. 00:01:06.184 --> 00:01:07.673 Steno had seen how gall stones 00:01:07.673 --> 00:01:10.426 form in wet organs by accretion. 00:01:10.426 --> 00:01:11.768 They obeyed molding principles 00:01:11.768 --> 00:01:13.556 he knew from the goldsmith trade, 00:01:13.556 --> 00:01:16.474 rules useful across disciplines for understanding solids 00:01:16.474 --> 00:01:18.771 by their structural relationships. 00:01:18.771 --> 00:01:20.310 Later, the Grand Duke of Tuscany 00:01:20.310 --> 00:01:21.977 had him dissect a shark. 00:01:21.977 --> 00:01:23.890 Its teeth resembled tongue stones, 00:01:23.890 --> 00:01:26.393 odd rocks seen inside other rocks 00:01:26.393 --> 00:01:28.979 in Malta and the mountains near Florence. 00:01:28.979 --> 00:01:31.203 Pliny the Elder, old Roman naturalist, 00:01:31.203 --> 00:01:33.530 said these fell from the sky. 00:01:33.530 --> 00:01:36.312 In the Dark Ages, folks said they were snake tongues, 00:01:36.312 --> 00:01:38.254 petrified by Saint Paul. 00:01:38.254 --> 00:01:40.828 Stenos saw that tongue stones were shark teeth 00:01:40.828 --> 00:01:42.393 and vice versa, 00:01:42.393 --> 00:01:45.003 with the same signs of structural growth. 00:01:45.003 --> 00:01:47.757 Figuring similar things are made in similar ways, 00:01:47.757 --> 00:01:49.396 he argued the ancient teeth 00:01:49.396 --> 00:01:50.724 came from ancient sharks 00:01:50.724 --> 00:01:53.679 in waters that formed rock around the teeth 00:01:53.679 --> 00:01:55.605 and became mountains. 00:01:55.605 --> 00:01:58.637 Rock layers were once layers of watery sediment, 00:01:58.637 --> 00:02:00.280 which would lay out horizontally, 00:02:00.280 --> 00:02:01.390 one atop another, 00:02:01.390 --> 00:02:03.105 oldest up to newest. 00:02:03.105 --> 00:02:04.726 If layers were deformed, 00:02:04.726 --> 00:02:05.200 tilted, 00:02:05.200 --> 00:02:06.026 cut by a fault, 00:02:06.026 --> 00:02:07.146 or a canyon, 00:02:07.146 --> 00:02:09.611 that change came after the layer formed. 00:02:09.611 --> 00:02:10.779 Sounds simple today; 00:02:10.779 --> 99:59:59.999 back then, revolutionary. 99:59:59.999 --> 99:59:59.999 He'd invented stratigraphy 99:59:59.999 --> 99:59:59.999 and laid geology's ground work. 99:59:59.999 --> 99:59:59.999 By finding one origin for shark teeth from two eras 99:59:59.999 --> 99:59:59.999 by stating natural laws ruling the present 99:59:59.999 --> 99:59:59.999 also ruled the past, 99:59:59.999 --> 99:59:59.999 Steno planted seeds for uniformitarianism, 99:59:59.999 --> 99:59:59.999 the idea that the past was shaped by processes 99:59:59.999 --> 99:59:59.999 observable today. 99:59:59.999 --> 99:59:59.999 In the 18th and 19th centuries, 99:59:59.999 --> 99:59:59.999 English uniformitarian geologists, 99:59:59.999 --> 99:59:59.999 James Hutton and Charles Lyell, 99:59:59.999 --> 99:59:59.999 studied current, very slow rates 99:59:59.999 --> 99:59:59.999 of erosion and sentimentation 99:59:59.999 --> 99:59:59.999 and realized the Earth had to be way older 99:59:59.999 --> 99:59:59.999 than the biblical guestimate, 6000 years. 99:59:59.999 --> 99:59:59.999 Out of their work came the rock cycle, 99:59:59.999 --> 99:59:59.999 which combined with plate tectonics 99:59:59.999 --> 99:59:59.999 in the mid-twentieth century 99:59:59.999 --> 99:59:59.999 to give us the great molten-crusting, quaking, 99:59:59.999 --> 99:59:59.999 all-encircling theory of the Earth, 99:59:59.999 --> 99:59:59.999 from a gall stone to a 4.5 billion year old planet. 99:59:59.999 --> 99:59:59.999 Now think bigger, 99:59:59.999 --> 99:59:59.999 take it to biology. 99:59:59.999 --> 99:59:59.999 Say you see shark teeth in one layer 99:59:59.999 --> 99:59:59.999 and a fossil of an organism 99:59:59.999 --> 99:59:59.999 you've never seen under that. 99:59:59.999 --> 99:59:59.999 The deeper fossil's older, yes? 99:59:59.999 --> 99:59:59.999 You now have evidence 99:59:59.999 --> 99:59:59.999 of the origin and extinction of species over time. 99:59:59.999 --> 99:59:59.999 Get uniformitarian. 99:59:59.999 --> 99:59:59.999 Maybe a process still active today 99:59:59.999 --> 99:59:59.999 caused changes not just in rocks, but in life. 99:59:59.999 --> 99:59:59.999 It might also explain similarities and differences 99:59:59.999 --> 99:59:59.999 between species 99:59:59.999 --> 99:59:59.999 found by anatomists like Steno. 99:59:59.999 --> 99:59:59.999 It's a lot to ponder, 99:59:59.999 --> 99:59:59.999 but Charles Darwin had the time 99:59:59.999 --> 99:59:59.999 on a long trip to the Galapagos, 99:59:59.999 --> 99:59:59.999 reading a copy of his friend 99:59:59.999 --> 99:59:59.999 Charles Lyell's "Principles of Geology," 99:59:59.999 --> 99:59:59.999 which Steno sort of founded. 99:59:59.999 --> 99:59:59.999 Sometimes giants stand on the shoulders 99:59:59.999 --> 99:59:59.999 of curious little people. 99:59:59.999 --> 99:59:59.999 Nicholas Steno helped evolve evolution, 99:59:59.999 --> 99:59:59.999 broke ground for geology, 99:59:59.999 --> 99:59:59.999 and showed how unbiased, empirical observation 99:59:59.999 --> 99:59:59.999 can cut across intellectual borders 99:59:59.999 --> 99:59:59.999 to deepen our perspective. 99:59:59.999 --> 99:59:59.999 His finest accomplishment, though, 99:59:59.999 --> 99:59:59.999 may be his maxim, 99:59:59.999 --> 99:59:59.999 casting the search for truth 99:59:59.999 --> 99:59:59.999 beyond our senses and our current understanding 99:59:59.999 --> 99:59:59.999 as the pursuit of the beauty 99:59:59.999 --> 99:59:59.999 of the as-yet unknown. 99:59:59.999 --> 99:59:59.999 Beautiful is what we see, 99:59:59.999 --> 99:59:59.999 more beautiful is what we know, 99:59:59.999 --> 99:59:59.999 most beautiful, by far, is what we don't.