"But therein also lies a built-in contradiction. If we are ficcardano price gbp coingeckotive, we have no right to 'believe' anything at all. In which case this whole telephone conversation is purely imaginary."
"Bingo."aes crypto javaAlberto let Sophie in. He was dressed in yet another costume. It wasn't all that different from last time, but today there were hardly any braidings, bows, or lace.
"But that's not all," Sophie said."What do you mean?""Didn't you find the note in the mailbox?""Oh, that. I threw it away at once.""I don't care if he laughs every time he thinks of Berkeley. But what is so funny about that particular philosopher?"
"We'll have to wait and see.""But today is the day you're going to talk about him, isn't it?""The first phase was a new scientific method. This made the technical revolution itself possible, and the technical breakthrough opened the way for every invention since. You could say that man had begun to break away from his natural condition. Nature was no longer something man was simply a part of. 'Knowledge is power,' said the English philosopher Francis Bacon, thereby underlining the practical value of knowledge-- and this was indeed new. Man was seriously starting to intervene in nature and beginning to control it."
"But not only in a good way?""No, this is what I was referring to before when I spoke of the good and the evil threads that are constantly intertwined in everything we do. The technical revolution that began in the Renaissance led to the spinning jenny and to unemployment, to medicines and new diseases, to the improved efficiency of agriculture and the impoverishment of the environment, to practical appliances such as the washing machine and the refrigerator and pollution and industrial waste. The serious threat to the environment we are facing today has made many people see the technical revolution itself as a perilous maladjustment to natural conditions. It has been pointed out that we have started something we can no longer control. More optimistic spirits think we are still living in the cradle of technology, and that although the scientific age has certainly had its teething troubles, we will gradually learn to control nature without at the same time threatening its very existence and thus our own.""Which do you think?""I think perhaps there may be some truth in both views. In some areas we must stop interfering with nature, but in others we can succeed. One thing is certain: There is no way back to the Middle Ages. Ever since the Renaissance, mankind has been more than just part of creation. Man has begun to intervene in nature and form it after his own image. In truth, 'what a piece of work is man!' "
"We have already been to the moon. What medieval person would have believed such a thing possible?""No, that's for sure. Which brings us to the new world view. All through the Middle Ages people had stood beneath the sky and gazed up at the sun, the moon, the stars, and the planets. But nobody had doubted that the earth was the center of the universe. No observations had sown any doubt that the earth remained still while the 'heavenly bodies' traveled in their orbits around it. We call this the geocentric world picture, or in other words, the belief that everything revolves around the earth. The Christian belief that God ruled from on high, up above all the heavenly bodies, also contributed to maintaining this world picture."
"I wish it were that simple!""But in 1543 a little book was published entitled On the Revolutions of the Celestial Spheres. It was written by the Polish astronomer Nicolaus Copernicus, who died on the day the book was published. Copernicus claimed that it was not the sun that moved round the earth, it was vice versa. He thought this was completely possible from the observations of the heavenly bodies that existed. The reason people had always believed that the sun went round the earth was that the earth turns on its own axis, he said. He pointed out that all observations of heavenly bodies were far easier to understand if one assumed that both the earth and the other planets circle around the sun. We call this the heliocentric world picture, which means that everything centers around the sun.""And that world picture was the right one?""Not entirely. His main point--that the earth moves round the sun--is of course correct. But he claimed that the sun was the center of the universe. Today we know that the sun is only one of an infinite number of stars, and that all the stars around us make up only one of many billions of galaxies. Copernicus also believed that the earth and the other planets moved in circular orbits around the sun."
"Don't they?""No. He had nothing on which to base his belief in the circular orbits other than the ancient idea that heavenly bodies were round and moved in circles simply because they were 'heavenly.' Since the time of Plato the sphere and the circle had been considered the most per-fect geometrical figures. But in the early 1600s, the German astronomer Johannes Kepler presented the results of comprehensive observations which showed that the planets move in elliptical--or oval--orbits with the sun at one focus. He also pointed out that the speed of a planet is greatest when it is closest to the sun, and that the farther a planet's orbit is from the sun the slower it moves. Not until Kepler's time was it actually stated that the earth was a planet just like other planets. Kepler also emphasized that the same physical laws apply everywhere throughout the universe.""How could he know that?""Because he had investigated the movements of the planets with his own senses instead of blindly trusting ancient superstitions. Galileo Galilei, who was roughly contemporary with Kepler, also used a telescope to observe the heavenly bodies. He studied the moon's craters and said that the moon had mountains and valleys similar to those on earth. Moreover, he discovered that the planet Jupiter had four moons. So the earth was not alone in having a moon. But the greatest significance of Galileo was that he first formulated the so-called Law of Inertia."
"And that is?""Galileo formulated it thus: A body remains in the state which it is in, at rest or in motion, as long as no external force compels it to change its state."
"If you say so.""But this was a significant observation. Since antiquity, one of the central arguments against the earth moving round its own axis was that the earth would then move so quickly that a stone hurled straight into the air would fall yards away from the spot it was hurled from."
"So why doesn't it?""If you're sitting in a train and you drop an apple, it doesn't fall backward because the train is moving. It falls straight down. That is because of the law of inertia. The apple retains exactly the same speed it had before you dropped it.""I think I understand.""Now in Galileo's time there were no trains. But if you roll a ball along the ground--and suddenly let go...""... it goes on rolling ...""... because it retains its speed after you let go."
"But it will stop eventually, if the room is long enough.""That's because other forces slow it down. First, the floor, especially if it is a rough wooden floor. Then the force of gravity will sooner or later bring it to a halt. But wait, I'll show you something."
Alberto Knox got up and went over to the old desk. He took something out of one of the drawers. When he returned to his place he put it on the coffee table. It was just a wooden board, a few millimeters thick at one end and thin at the other. Beside the board, which almost covered the whole table, he laid a green marble."This is called an inclined plane," he said. "What do you think will happen if I let go the marble up here, where the plane is thickest?"
Sophie sighed resignedly."I bet you ten crowns it rolls down onto the table and ends on the floor."
"Let's see."Alberto let go of the marble and it behaved exactly as Sophie had said. It rolled onto the table, over the tabletop, hit the floor with a little thud and finally bumped into the wall."Impressive," said Sophie."Yes, wasn't it! This was the kind of experiment Galileo did, you see."
"Was he really that stupid?""Patience! He wanted to investigate things with all his senses, so we have only just begun. Tell me first why the marble rolled down the inclined plane."
"It began to roll because it was heavy.""All right. And what is weight actually, child?"
"That's a silly question.""It's not a silly question if you can't answer it. Why did the marble roll onto the floor?"
"Because of gravity.""Exactly--or gravitation, as we also say. Weight has something to do with gravity. That was the force that set the marble in motion."Alberto had already picked the marble up from the floor. He stood bowed over the inclined plane with the marble again."Now I shall try to roll the marble across the plane," he said. "Watch carefully how it moves."
Sophie watched as the marble gradually curved away and was drawn down the incline."What happened?" asked Alberto.
"It rolled sloping because the board is sloping.""Now I'm going to brush the marble with ink ... then perhaps we can study exactly what you mean by sloping."
He dug out an ink brush and painted the whole marble black. Then he rolled it again. Now Sophie could see exactly where on the plane the marble had rolled because it had left a black line on the board."How would you describe the marble's path?"