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This image of the Vitruvian Man,

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taken from Leonardo's sketches,

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has become one of the most recognizable

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symbols of the Renaissance.

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But why?

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It's a simple pen and ink drawing, right?

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Wrong!

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Let's start to answer this question

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with a math problem.

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I know how to calculate the area of a circle.

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I take the value for pi

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and multiply it by the radius squared.

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I also know how to take the area of a square.

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I multiply the base by itself.

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But, how can I take the area of a circle

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and create a square with an equal area?

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This is a problem often called "squaring a circle"

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that was first proposed in the ancient world.

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And like many of ideas of the ancient world,

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it was given new life during the Renaissance.

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As it turns out,

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this problem is impossible to solve

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because of the nature of pi,

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but that's another story.

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Leonardo's sketch,

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which is influenced by the writings

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of a Roman architect, Vitruvius,

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places a man firmly at the center

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of a circle and a square.

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Vitruvius claimed the navel

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is the center of the human body

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and that if one takes a compass

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and places the fixed point on the navel,

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a circle can be drawn perfectly around the body.

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Additionally, Vitruvius recognized

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that arm span and height

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have a nearly perfect correspondence in the human body,

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thus placing the body perfectly inside a square as well.

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Leonardo used the ideas of Vitruvius

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to solve the problem of squaring a circle metaphorically

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using mankind as the area for both shapes.

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Leonardo wasn't just thinking about Vitruvius, though.

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There was an intellectual movement

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in Italy at the time

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called Neoplatonism.

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This movement took an old concept

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from the 4th century developed by Plato and Aristotle,

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called "The Great Chain of Being".

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This belief holds that the universe is a hierarchy

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resembling a chain,

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and that chain starts at the top with God,

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then travels down through the angels,

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planets,

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stars,

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and all lifeforms

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before ending with demons and devils.

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Early in this philosophic movement,

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it was thought that mankind's place in this chain

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was exactly in the center.

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Because humans have a mortal body

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accompanied by an immortal soul,

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we divide the universe nicely in half.

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Around the time Leonardo sketched

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the Vitruvian Man, however,

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a Neoplatonist named Pico della Mirandola

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had a different idea.

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He pried mankind off the chain

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and claimed that humans have a unique ability

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to take any position they want.

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Pico claimed that God desired

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a being capable of comprehending

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the beautiful and complicated universe he had created.

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This led to the creation of mankind,

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which he placed at the center of the universe

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with the ability to take whatever form he pleases.

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Mankind, according to Pico,

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can crawl down the chain and behave like an animal

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or crawl up the chain and behave like a god,

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it's our choice.

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Looking back at the sketch,

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we can see that by changing the position of the man,

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he can fill the irreconcillible areas

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of a circle and a square.

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If geometry is the language the universe is written in,

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then this sketch seems to say

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we can exist within all its elements.

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Mankind can fill whatever shape

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he pleases geometrically

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and philosophically as well.

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In this one sketch,

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Leondardo was able to combine

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the mathematics,

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religion,

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philosophy,

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architecture,

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and artistic skill of his age.

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No wonder it has become such an icon

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for the entire time period.