The Ascent of Man (35 page)

And now we come to a part of Szilard’s personality which was characteristic of scientists
at that time, but which he expressed most clearly and loudly. He wanted to keep the patent secret. He wanted to prevent science from being misused. And, in fact, he assigned the patent to the British Admiralty, so that it was not published until after the war.

But meanwhile war was becoming more and more threatening. The march of progress in nuclear physics and the march of Hitler went step by
step, pace by pace, in a way that we forget now. Early in 1939 Szilard wrote to Joliot Curie asking him if one could make a prohibition on publication. He tried to get Fermi not to publish. But finally, in August of 1939, he wrote a letter which Einstein signed and sent to President Roosevelt, saying (roughly), ‘Nuclear energy is here. War is inevitable. It is for the President to decide what scientists
should do about it’.

But Szilard did not stop. When in 1945 the European war had been won, and he realised that the bomb was now about to be made and used on the Japanese, Szilard marshalled protest everywhere he could. He wrote memorandum after memorandum.
One memorandum to President Roosevelt only failed because Roosevelt died during the very days that Szilard was transmitting it to him. Always Szilard wanted the bomb to be tested openly before the Japanese and an international audience, so that the Japanese should know its power and should surrender before people died.

As you know, Szilard failed, and with him the community of scientists failed.
He did what a man of integrity could do. He gave up physics and turned to biology – that is how he came to the Salk Institute – and persuaded others too. Physics had been the passion of the last fifty years, and their masterpiece. But now we knew that it was high time to bring to the understanding of life, particularly human life, the same singleness of mind that we had given to understanding
the physical world.

The first atomic bomb was dropped on Hiroshima in Japan on 6 August 1945 at 8.15 in the morning. I had not been long back from Hiroshima when I heard someone say, in Szilard’s presence, that it was the tragedy of scientists that their discoveries were used for destruction. Szilard replied, as he more than anyone else had the right to reply, that it was not the tragedy of scientists:
‘it is the tragedy of mankind’.

There are two parts to the human dilemma. One is the belief that the end justifies the means. That push-button philosophy, that deliberate deafness to suffering, has become the monster in the war machine. The other is the betrayal of the human spirit: the assertion of dogma that closes the mind, and turns a nation, a civilisation, into a regiment of ghosts – obedient
ghosts, or tortured ghosts.

It is said that science will dehumanise people and turn them into numbers. That is false, tragically false. Look for yourself. This is the concentration camp and crematorium at Auschwitz. This is where people were turned into numbers. Into this pond were flushed the ashes of some four million people. And that was not done by gas. It was done by arrogance. It was done
by dogma. It was done by ignorance. When people believe that they have absolute knowledge, with no test in reality, this is how they behave. This is what men do when they aspire to the knowledge of gods.

Science is a very human form of knowledge. We are always at the brink of the known, we always feel forward for what is to be hoped. Every judgment in science stands on the edge of error, and
is personal. Science is a tribute to what we can know although we are fallible. In the end the words were said by Oliver Cromwell: ‘I beseech you, in the bowels of Christ, think it possible you may be mistaken’.

I owe it as a scientist to my friend Leo Szilard, I owe it as a human being to the many members of my family who died at Auschwitz, to stand here by the pond as a survivor and a witness.
We have to cure ourselves of the itch for absolute knowledge and power. We have to close the distance between the push-button order and the human act. We have to touch people.

In the nineteenth century the city of Vienna was the capital of an Empire which held together a multitude of nations and languages. It was a famous centre of music, literature and the arts. Science was suspect in conservative Vienna, particularly biological science. But unexpectedly Austria was also the seedbed for one scientific idea (and in biology)
that was revolutionary.

At the old university of Vienna the founder of genetics, and therefore of all the modern life sciences, Gregor Mendel, got such little university education as he had. He came at a historic time in the struggle between tyranny and freedom of thought. In 1848, shortly before he came, two young men had published far away in London, in German, a manifesto which begins with
the phrase: ‘Ein Gespenst geht um Europa’, ‘a spectre is haunting Europe’, the spectre of communism.

Of course, Karl Marx and Friedrich Engels in
The Communist Manifesto
did not create the revolutions in Europe; but they gave them the voice. It was the voice of insurrection. A spate of disaffection ran though Europe against the Bourbons, the Habsburgs, and governments everywhere. Paris was in
turmoil in February of 1848, and Vienna and Berlin followed. And so in the University Square in Vienna in March 1848 students protested and fought the police. The Austrian Empire, like others, shook. Metternich resigned and fled to London. The Emperor abdicated.

Emperors go, but empires remain. The new Emperor of Austria was a young man of eighteen, Franz Josef, who reigned like a medieval autocrat
until the ramshackle empire fell to pieces during the First World War. I still remember Franz Josef when I was a small boy; like other Habsburgs, he had the long lower lip and pouched mouth which Velazquez has painted in the Spanish kings, and which is now recognised as a dominant genetic trait.

When Franz Josef came to the throne the patriots’ speeches fell silent; the reaction under the young
Emperor was total. At that moment the ascent of man was quietly set off in a new direction by the arrival at the University of Vienna of Gregor Mendel. He had been born Johann Mendel, a farmer’s son; Gregor was the name he was given when he became a monk just before this, frustrated by poverty and lack of education. He remained all his life a farm boy in the way he went about his work, not a professor
nor a gentleman naturalist like his contemporaries in England; he was a kitchen-garden naturalist.

Mendel had become a monk to get an education, and his abbot put him into the University of Vienna to get a formal diploma as a teacher. But he was nervous and was not a clever student. His examiner wrote that he ‘lacks insight and the requisite clarity of knowledge’ and failed him. The farm boy
become monk had no choice except to withdraw again into the anonymity of the monastery at Brno in Moravia, which is now part of Czechoslovakia.

When Mendel came back from Vienna in 1853 he was, at the age of thirty-one, a failure. He had been sent by the Augustinian Order of St Thomas in Brno, and they were a teaching order. The Austrian Government wanted the bright boys among the peasantry taught by monks. Theirs is the library not so much of a
monastery as of a teaching order. And Mendel had failed to qualify as a teacher. He had to make up his mind whether to live the rest of his life as a failed teacher, or as – what? As the boy they called Hansl on the farm, the young man Johann from the farm, he decided; not as the monk Gregor. He went back in thought to what he had learned on the farm and had been fascinated by ever since: plants.

At Vienna he had been under the influence of the one fine biologist he ever met, Franz Unger, who took a concrete, practical view of inheritance: no spiritual essences, no vital forces, stick to the real facts. And Mendel decided to devote his life to practical experiments in biology, here in the monastery. A bold, silent, and secret stroke, I think, because the local bishop would not even allow
the monks to teach biology.

Mendel began his formal experiments about two or three years after he came back from Vienna, say about 1856. He says in his paper that he worked for eight years. The plant that he had chosen, very carefully, is the garden pea. He picked out seven characters for comparison: shape of seed, colour of seed, and so on, finishing his list with tall in stem versus short-stemmed.
And that last character is the one that I have chosen to display: tall versus short.

We do the experiment exactly throughout as Mendel did. We start by making a hybrid of tall and short, choosing the parent plants as Mendel specified:

In experiments with this character, in order to be able to discriminate with certainty, the long axis of six to seven feet was always crossed with the short one
of ¾ of a foot to 1½ feet.

In order to make sure that the short plant does not fertilise itself, we emasculate it. And then we artificially inseminate it from the tall plant.

The process of fertilisation takes its course. The pollen tubes grow down the ovules. The pollen nuclei (the equivalent of sperm in an animal) go down the pollen tubes and reach the ovules just as they do in any other fertilised
pea. The plant bears pods that do not yet, of course, reveal their character.

The peas from the pods are now planted. Their development is at first indistinguishable from that of any other garden peas. But though they are only the first generation of hybrid offspring, their appearance when fully grown will already be a test of the traditional view of inheritance held by botanists then and long
afterwards. The traditional view was that the characters of hybrids fall between the characters of their parents. Mendel’s view was radically different, and he had even guessed a theory to explain it.

Mendel had guessed that a simple character is regulated by two particles (we now call them genes). Each
parent contributes one of the two particles. If the two particles or genes are different,
one will be dominant and the other recessive. The crossing of tall peas with short is a first step in seeing if this is true. And lo and behold, the first generation of hybrids, when fully grown, are all tall. In the language of modern genetics, the character tall is dominant over the character short. It is not true that the hybrids average the height of their parents; they are all tall plants.

Now the second step: we form the second generation as Mendel did. We fertilise the hybrids, this time with their own pollen. We allow the pods to form, plant the seeds, and here is the second generation. It is not all of anything, for it is not uniform; there is a majority of tall plants, but a significant minority of short plants. The fraction of the total that consists of short plants should
be calculable from Mendel’s guess about heredity; for if he was right, each hybrid in the first generation carried one dominant and one recessive gene. Therefore in one mating out of every four between first generation hybrids, two recessive genes have come together, and as a result one plant out of every four should be short. And so it is: in the second generation, one plant out of four is short,
and three are tall. This is the famous ratio of one out of four, or one to three, that everyone associates with Mendel’s name – and rightly so. As Mendel reported,