Introducing Darwin E-Book

Jonathan Miller

• Herausgeber: Icon Books
• Kategorie: Wissenschaft und neue Technologien
• Serie: Graphic Guides
• Sprache: Englisch
• Veröffentlichungsjahr: 2015

Seitenzahl: 100

Beschreibung

Progress in genetics today would not be possible without Darwin's revolution, but the mysterious man who laid the rational basis for undermining belief in God's creation was remarkable timid. He spent most of his life in seclusion; a semi-invalid, riddled with doubts, fearing the controversy his theories might unleash. In this brilliantly lucid book - a classic originally published in 1982 - Jonathan Miller unravels Darwin's life and his contribution to biology, and traces the path from his scientific predecessors to the later modifications that his own evolutionary theories required. Introducing Darwin brings alive the difficult progress from pre-Darwinian thinking to modern genetics and the devastatingly important impact of one man on our fundamental understanding of biology, life and ourselves.

Leseprobe

Published by Icon Books Ltd, Omnibus Business Centre, 39–41 North Road, London N7 9DP Email: [email protected]

ISBN: 978-184831-117-6

Text copyright © 2012 Icon Books Ltd

Illustrations copyright © 2012 Icon Books Ltd

The author and illustrator has asserted their moral rights

Originating editor: Richard Appignanesi

No part of this book may be reproduced in any form, or by any means, without prior permission in writing from the publisher.

Contents

Cover

Title Page

Copyright

Creationism

The Relative Youth of the Earth

The Permanence of the Earth’s Physical Structure

The Permanence of Living Things

Progressionism

The Argument from Design

Essentialism

Uniformitarianism

Facts In Favour Of Evolution Before Darwin

The Descent of Darwin

1. The Succession of Types

2. Representative Types

3. The Evidence of Ocean Islands

Fear of Controversy & Persecution

Darwin’s Religious Beliefs

Scientific Caution

The Theory Of Pangenesis

Weismanns Neo~Darwinism

The Central Dogma

Gregor Mendel’s Discovery

Mutation

Mutation vs. Variation

The New Synthesis

Isolating Mechanisms

Further Reading

Index

WHEN DARWIN’S FRIEND & COLLEAGUE T.H. HUXLEY FIRST READ THE ORIGIN OF SPECIES IN 1859 HE SAID TO HIMSELF …… … “ HOW STUPID NOT TO HAVE THOUGHT OF IT BEFORE!”

THIS DOESN’T MEAN HE THOUGHT THE BOOK WAS TRIVIAL ON THE CONTRARTY… HRRMPH!

In fact The Origin of Species was a popular success. The first printing sold out on the day of publication. This alone distinguished it from most other great theories in the history of science. Isaac Newton’s great work was, and still is, inaccessible to the general reader. The mathematical argument is so abstruse that it took many years of patient analysis before the scientific community fully understood its implications. The fact that Darwin’s theory could be put so simply may have been one of the reasons Huxley asked himself why nobody had thought of it before.

WHA-?

This impression was reinforced by darwin’s own personality. He seemed little more than an affable amateur, some one whose formal education had been a series of humilating disasters.

None of this discredits darwin’s achievement. But it does reveal something rather peculiar about it.

HERE’S A THEORY WHICH CAN BE CONCEIVED AND CONVEYED IN EVERYDAY LANGUAGE BY SOMEONE – BY HIS OWN ADMISSION – POORLY QUALIFIED . . . WHY HAD NO ONE THOUGHT OF IT BEFORE?

In fact, one reason why Darwin issued his book when he did, is that he was panicked into publishing by receiving through the post a summary of the theory which he’d been secretly nursing for twenty years.

By 1859, the scientific atmosphere was saturated with the possibility of evolution. It was only a matter of time before someone stumbled on the truth. Nevertheless the question remains: why hadn’t it been recognized before?

One answer might be that the necessary facts weren’t available until Darwin discovered them, and that he was lucky to find the missing pieces which allowed him to make sense of all the rest. But this isn’t true either, for although Darwin made many important observations of his own, the facts which would have supported his theory were already known and had been widely discussed before. No one it seems had recognized their significance. Or not entirely.

WHY NOT? WHY DIDN’T THEY ‘SEE’ WHAT DARWIN SAW? WHEN A SCIENTIST RECOGNIZES A SIGNIFICANT NEW PATTERN WITHOUT ANY NEW FEATURES HAVING BEEN ADDED TO IT, THE PROCESS MUST BE SIMILAR TO WHAT HAPPENS WHEN A ‘PUZZLE’ PICTURE SUDDENLY CHANGES APPEARANCE… THE PATTERN OF THESE LINES MAY LOOK LIKE THE PROFILE OF A BEAUTIFUL YOUNG WOMAN… BUT IF YOU LOOK AT IT IN ANOTHER WAY YOU MAY SUDDENLY SEE AN UGLY GYPSY ‘SEEING’ ME AS A RABBIT… … PREVENTS YOU FROM SEEING ME AS A DUCK FACING IN THE OPPOSITE DIRECTION THE PATTERN OF LINES IN A ‘NECKER CUBE’ LOOKS LIKE THE CORNER OF A ROOM. BUT IT CAN AS EASILY BECOME THE OUTER EDGE OF A SOLID CUBE.

The point is that a strong preconception about what a pattern means, what it represents, can stop you seeing it in any other way. Presumably this happened to Darwin’s predecessors and some of his contemporaries as well. They failed to ‘see’ what Darwin ‘saw’, not because they were short of facts, but because they had reasons for ‘seeing’ the facts in a different way. They saw a duck and Darwin taught them to recognize a rabbit. Huxley’s surprise was recognizing something that had been in front of his eyes all along.

The question is, what preconceptions led scientists to overlook the pattern that Darwin eventually saw? (Another question you will have to ask is whether Darwin really saw what he claimed to have seen, and whether his own position was quite as revolutionary as it has been said to be.)

There were several preconceptions which delayed the recognition of evolution in nature. And they arose from man’s tendency to project the image of his own mind onto the world around him. 1. The biblical notion of special creation. 2. The Greek philosophical notion of Ideal Forms.

Creationism

MOST SOCIETIES EXPLAIN THE ORIGIN OF THE LIVING WORD AS AN ACT OF PROVIDENTIAL DESIGN. FOR WESTERN EUROPE, THIS DOCTRINE IS ENSHRINED IN THE BIBLE

According to the Book of Genesis God formed the world and stocked it with a wealth of clearly distinguishable living forms. Christian theologians extracted several important dogmas from this myth.

The Relative Youth of the Earth

CHRISTIAN WRITERS ARGUED WITH ONE ANOTHER ABOUT THE EXACT DATE OF THE CREATION. BUT THEY ALL AGREED IT WAS A COMPARATIVELY RECENT EVENT… TIME WE MAY COMPREHEND, ‘TIS BUT 5 DAYS ELDER THAN OURSELVES & HATH THE SAME HOROSCOPE WITH THE WORLD. THE UNIVERSE IS 6000 YEARS OLD-THAT’S MY RULING!

For Christians, physical history was a short action-packed chapter bracketed between endless tracts of eternity. Such a short time-span ruled out the possibility of gradual change. Until scientists recognized that the age of the earth had to be reckoned in billions of years, evolutionary thought had no chance of gaining a foothold. This consideration will return to plague Darwin in his later years.

The Permanence of the Earth’s Physical Structure

According to orthodox Christian thought, the appearance of the modern earth was the result of two factors: 1. The shape God had given it in the beginning. 2. The damage he inflicted on it when he punished man with the flood. The globe was a static ruin, and hadn’t changed its basic structure since the deluge ploughed up the mountains and excavated the valleys. In a scene of such changeless monotony there was no need for living things to alter.

The Permanence of Living Things

Once Adam had named all the plants and animals these inaugural forms bred true to type and never changed their identity.

WHEN GOD INUNDATED THE WORLD HE ORDERED NOAH TO SET ASIDE A REPRESENTATIVE PAIR OF EVERY LIVING TYPE, SO THAT AFTER THE FLOOD, THE WORLD WOULD BE REPOPULATED EXACTLY AS BEFORE.

For pious Christians it was an article of faith that the living world was an unaltered replica of the one which God had created at the outset. No species had been lost and none had been altered. Extinction was just as inconceivable as change.

For a long time this dogma led scientists to disregard the significance of fossils. The fact that these ‘figured stones’ happened to resemble shellfish etc. was often dismissed as an interesting coincidence, or as a sign that God had playfully decorated his rocks with ornamental replicas of living things.

ONCE THEIR ORGANIC CHARACTER WAS RECOGNIZED IT POSED AN AWKWARD PROBLEM. THE 17TH CENTURY NATURALIST, JOHN RAY ANNOUNCED THAT: IT WOULD FOLLOW THAT MANY SPECIES OF SHELLFISH ARE LOST OUT OF THE WORLD WHICH PHILOSOPHERS HAVE HITHERTO BEEN UNWILLING TO ADMIT, ESTEEMING THE DESTRUCTION OF ANY ONE SPECIES A DISMEMBERING OF THE UNIVERSE AND RENDERING IT IMPERFECT; WHEREAS THEY THINK THE DIVINE PROVIDENCE IS ESPECIALLY CONCERNED TO PRESERVE AND SECURE THE WORK OF THE CREATION.

Instead of allowing the accidental extinction of a few imperfect types, it was less embarrassing to assume that God had deliberately destroyed all his living handiwork, only to recreate it all over again once man had been taught a lesson.

This idea had to be elaborated as geological discoveries revealed not one but many layers of extinct life. By the end of the 18th century, it was generally acknowledged that the rocks contained a whole record of a previous existence.

In order to avoid the blasphemous implication of continuous change, scientists introduced the theory of intermittent catastrophes. Instead of one flood it was now suggested that there had been many — Noah’s being the last. After each cataclysm God had generously replenished the globe with a fresh stock of living things. It soon became apparent, however, that these successive creations were not simply repetitions of one another. Each fossil level showed a distinct advance on its predecessor. Invertebrates appeared in the lowest and oldest strata. Then fish began to figure. Reptiles and birds appeared later, then mammals and finally man.

THESE FINDINGS INTRODUCED THE IDEA OF PROGRESSION!

Progressionism

God, it seemed, had staggered his creative efforts, allowing nature to develop in a series of separate stages. This Progressionism had nothing to do with evolution. There was no question of descent, no transition from one stage to the next. Each level represented a unique act of creation.

THE CONNECTION IS NOT THE CONSEQUENCE OF A DIRECT LINEAGE BETWEEN THE FAUNAS OF DIFFERENT AGES. THERE IS NOTHING LIKE PARENTAL DESCENT CONNECTING THEM. THE FISHES OF THE PALAEOZOIC AGE ARE IN NO RESPECT THE ANCESTORS OF THE REPTILES OF THE SECONDARY AGE, NOR DOES MAN DESCEND FROM THE MAMMALS WHICH PRECEDED HIM IN THE TERTIARY AGE. THE LINK BY WHICH THEY ARE CONNECTED IS OF A HIGHER IMMATERIAL NATURE; THEIR CONNECTION IS TO BE SOUGHT IN THE VIEW OF THE CREATOR HIMSELF, WHOSE AIM IN FORMING THE EARTH . . . . . WAS TO INTRODUCE MAN UPON ITS SURFACE.

The Argument from Design

Behind the dogmas of Creationism lay the notion of intelligent providential design. Although this is not explicitly mentioned in the Book of Genesis, it became the most forceful argument in favour of a Special Creation.

As biological research developed during the 18th century, scientists were more and more struck by the fitness and efficiency of living things. Fins, feathers, hearts, lungs and eyes were so admirably adapted to the functions they served, it seemed inconceivable they could have arisen spontaneously — let alone by chance. They must have been deliberately designed. Here at last was a rational argument in favour of God’s existence. It was no longer necessary to rely on Biblical faith since the very facts of science bore witness to the activity of an intelligent designer.

This Natural Theology gave traditional Christianity a new lease of life. When Darwin was growing up, the argument from design was a most powerful objection to evolutionary thought. Nature was a living record of God’s benèvolent foresight.

SUPPOSE ONE HAD NEVER SEEN A WATCH BEFORE THE MOST FAMOUS EXPRESSION OF THIS ARGUMENT WAS BISHOP PALEY’S EVIDENCE OF CHRISTIANITY

NOW APPLY THIS PRINCIPLE TO THE EYE! THE TRANSPARENCY OF THE CORNEA, THE PRECISION OF THE LENS, AND THE ADJUSTABILITY OF THE PUPIL, ALL CO-OPERATE TO SERVE VISION. THE MARKS OF DESIGN ARE TOO STRONG TO BE GOTTEN OVER. DESIGN MUST HAVE A DESIGNER. THAT DESIGNER MUST BE A PERSON . . .

HOW COULD ONE EXPLAIN IT’S EXISTENCE? THE EFFICIENCY OF ITS MECHANISM . . . . . . WOULD FORCE ONE TO ASSUME THAT IT HAD BEEN DELIBERATELY DESIGNED AND THAT WOULD AUTOMATICALLY IMPLY THE EXISTENCE OF AN INTELLIGENT DESIGNER.

. . . THAT PERSON IS GOD?

Darwin knew Paley’s book by heart, and confessed that in his youth he had been enchanted by its unarguable logic. Even Huxley assumed that intelligent creation was the most plausible explanation for the beautiful efficiency of nature.

In the early years of the 19th century, the argument from design spearheaded the attack on evolutionary thought.

In England the religious dogmas of Creationism played an especially important part in delaying evolutionary thought. This was partly because the Anglican church was built-in to the political structure of Great Britain, and any threat to Christian orthodoxy implied an even greater threat to social stability.

Although the doctrine of Creationism played an important part in continental thought, the Philosophical Idealism of Plato