[BLANK_AUDIO] In, in this last video of lecture five, I'd like to talk of the incredible relationship between constraint and creativity. Again, do you need constraint to be creative? Sometimes yes, sometimes no. Let's take an example. Maurice Ravel, the, the composer, wrote a piece of music for piano for the left hands, for the left hand. Why? Because the brother of Wittgenstein, the philosopher, his brother, lost one of his arm during the war, and he was a pianist. Ravel wrote the concerto for the left hand, it's a constraint, but it's beautiful piece of music. Sometimes constraint is incredible. Django Rheinhardt, the famous guitarist, lost 2 fingers in the free. He developed a way to play guitar with only three fingers. What a constraint. And he is an incredible player. And so, you can have the feeling. Okay, you need constraint to be creative. No. Sometimes it's good, sometimes not good. Let's take painting. Painting for, during centuries, painters took for grant a constraint. We have to draw to copy, to imitate the nature. We have to portrait people. We have to describe exactly how is the landscape. 150 years ago, somebody invented photography. And what happened suddenly? The painter was freed from this constraint. Hey, you have photo, you can picture the world. And suddenly, painting became extremely creative because the constraint disappear. Again, there is no answer. Sometimes yes, sometimes no. Don't expect the rules. Unleash yourself, that's the way to be, to be creative. And to end this, this lecture, I want to pay a tribute to somebody. We mentioned, during lecture 3, Galileo Galilei. You remember, when you have all those people? I'm going to tell some stories about him. Because he had a lot of constraints, no computer, no watches, nothing, no, no scientific instruments. How did he do it? And that is something, extremely learning about the way creativity can work with constraint. I have three things to tell about Galileo. First thing, you remember during lecture one we compare logic and analogic? Logic within the deduction, and analogic as a help, as a tool to induce. He had one of his discovery where the moon around Jupiter and imagine for him, for the very first time with a telescope he looked at Jupiter. And he saw some dots moving just in front of Jupiter. He wrote in his text book, he wrote, ha, Jupiter has moons. How was this possible? Because our moon did exist, he could make an analogy between our moon and the moons. Analogy sometimes moves you from capital letter, the moon, to s, smaller letters. Moves, and analogy is a way Galileo used a lot to put forward his discoveries. The two other ideas I want to give up are this ones. At the time of Galileo, the paradigm in physics, was Aristotle. 1,800 years old paradigm. When Galileo was living during the Renaissance, the reference was Aristotle. And he went against Aristotle. He say, probably he's wrong. And on two points, he made a hit against Aristotle. The first hypothesis of Aristotle was, and I will use a tool. [SOUND] Aristotle said, heavy bodies are falling faster than light bodies. If I let them, this going to fall faster than this one. [SOUND] Galileo felt, this is not true. He was convinced. But how can I prove that? No instrument. I can not measure time, I can not picture, I have no compute, I have nothing. How can I prove Aristotle is wrong? He had an incredible idea. He did this. [SOUND] He organized this way. On one hand you had like a brick, on the other hand two half bricks. And if I do this, I ask you which side is going to fall faster? [BLANK_AUDIO] Same size. Same volume, same weight, same amount of biscuits in this case. You'll say the speed's going to be the same. Exactly. And that's how he proved Aristotle was wrong. If mentally you imagine on one hand a brick and in the other hand two half bricks, there is not a single reason why this side would fall slower than this one Aristotle was wrong. And it's amazing to see how the mind can help when truths are not available and that was the case at the time of Galileo. And another thing, of course, is even more incredible. And I go back to him. He was convinced, Aristotle was convinced, the speed of the fall is a constant. He was convinced of this one. For Aristotle, a body, a falling body, cover the same space in the same amount of time. First second, second second, third, et cetera down. And again, Galileo thought this is not true. He had this feeling, this intuition, there is an acceleration. He said, I'm sure the first second is this, the second is there, et cetera, et cetera. But how to prove it? No instruments. He had two bright ideas. The first one, he said, if I build a slope like this, I will keep proportions, so, I can slow the movement down with using a slope. And then he said, okay, fine. But even on a slope it goes very fast. What can I do? And here, the big think. He said, definitely, I cannot solve the problem with my eyes. Too fast. I will solve the problem with my ears. Look what he did. He use bells. And on the slope, and you can see the slope somewhere in the museum in Florence. On the slope he put bells at the same distance in the first try. He let the ball roll. And he hear, pum, pum, pum, pum, pum, pum, pum. He said, hey, there is an acceleration. There is definitely [INAUDIBLE]. He was so happy, but then he said, okay, there is an acceleration but I want to know which acceleration. And then he started to play with the bells. And he set the bells along the slope in such a way the reading remains constant [SOUND]. And when he achieved his goal he realized the distance between the bells were one, two, four, eight, et cetera. Amazing. That's the way he proved there was an acceleration and he even tell people it's always the square of the former one. [BLANK_AUDIO]