René Descartes 1596-1650

Great mathematician: x, y, z axis Physicist: angle of refraction 1st modern philosopher -> aware of ‘I’ Subjectivism (‘I’) Rationalism Mechanical world view

CONTEXT: Revolution in science

Science and research in the honour of God Descartes: extend knowledge and understand the world

Mechanical worldview

First microscope in the world It’s a mammoth First microscope in the world

He seeks to demonstrate the possibility of knowledge even from the most sceptical position. (This is due to him being annoyed by the scepticism from the Renaissance.) And from this, to establish a firm foundation for the sciences.

THOUGHT EXPERIMENT Scepticism: Descartes’ 3 waves of doubt: illusion, deception, dreaming (hyperbolic)

scepticism He tried to doubt everything, even those things that appeared obvious! His aim was to find things we can be 100% certain of Descartes noted that senses sometimes deceive us

1st wave: Illusion Descartes begins his method of doubt by considering that in the past he has been deceived by his senses: Things in the distance looked small; sticks in water appeared bent However, Descartes finally accepts that these could be perceptual illusions

Conclusion The occurrence of perceptual illusions are not commonplace enough to make us doubt our everyday knowledge There, the first wave of doubt isn’t enough to knock our knowledge off its feet We can continue to trust that most of our everyday perceptions accurately reflect the way the world is

But clearly, either way, I am a very handsome man. 2nd wave: Dreaming ‘There are no conclusive signs of which one can distinguish clearly between being awake and being asleep’. But clearly, either way, I am a very handsome man.

Scepticism and dreaming Descartes’ 2nd wave of doubt argues that we could be dreaming; this attacks all sense-perception, even the most ordinary and the most certain E.g. You cannot know that you are sitting on a chair because you cannot know you are not dreaming of sitting on a chair Go on…try and prove you’re not dreaming it.

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Dom Cobb (Leonardo DiCaprio) doesn't steal things, he steals ideas. INCEPTION… … is about a thief who possesses the power to enter into the dreams of others. Dom Cobb (Leonardo DiCaprio) doesn't steal things, he steals ideas. By projecting himself deep into the dreams of his targets, he can steal information.

The philosophy behind inception… Watch clip 4.22 min “Dreams feel real whilst we are in them. It is only when we wake up that we realise something was actually strange” Cobb Can Cobb possibly know whether or not he is dreaming?

Replies to dreaming Some philosophers have responded by saying that dreams are much less coherent than reality You may often dream that your teacher is a cactus but when you open your eyes, he rarely is

Descartes reply Descartes agrees that some dreams have less coherence than reality However, this one particular dream could be a perfect imitation of reality We cannot know that this particular moment is not a moment in a particularly realistic dream

Conclusion I cannot prove that I am not dreaming If I cannot prove that I am not dreaming than I cannot be sure my current sense experiences truly reflect the way the world is I therefore cannot be sure of any knowledge based on sense experience However, one thing I can be sure of is the truths of maths and logic…hurrah

The 3rd wave: Deception The evil demon For the sake of argument, Descartes next suggests that all of our experiences are produced by an evil demon who wants to deceive us The possibility of this being true means that none of my experiences are real All my beliefs about the external world and events in time are thrown into doubt because it is based on experience (which the evil demon controls) Even the truths of maths and logic could be lies!

How can thoughts be trusted when the evil demon can control them too? Can I trust my memories, if the evil demon controls the things in my mind? Can I trust others, if the evil demon controls all of my experiences? No! You can trust nothing hahahahahahhhahahhahhahhahahhahah(hic!) Curses…laughing always gives me hiccups

Putnam’s brain in a vat theory Descartes argument from deception appeals to an evil demon A modern version of that idea is that we are not really walking, talking human beings but simply brains in vats.

Putnam’s Brain in a vat theory Connected to my brain is a super-computer that feeds in just the right impulses to generate the illusion of reality So I still have sensations of touch, taste, sight etc but they do not reflect any sort of reality I cannot know that this is not true as things seem exactly the same as if I am a walking, talking human In this way, neither my senses nor my reasoning can be trusted. See if you can identify one good reason to believe you are not a brain in a vat…

Let’s try this: Choose one of the cards below. Keep your choice secret. Do not tell anyone else.

Now I want you to visualise your card in your mind as hard as you can for a moment or two. Try and really see it as if it were still in front of you To help me, I want you to SILENTLY say the name of your card in your mind three times Give me a minute….. I am accessing the programme that controls your thoughts

There, I have removed the card you were thinking of from the deck

Conclusion Descartes: God would not allow me to be deceived! My ideas are clear and distinct God is good and I can therefore trust that what I know clearly and distinctly must be true or God would be allowing me to be deceived

Cogito ergo sum! Descartes concluded that there was only one thing he could be sure of... THINKING! ‘I’ think! If we doubt and question the existence of everything in this classroom What is the ONE thing you would be most sure of and why?

I think, therefore I am! He found an unshakeable truth that no doubt could assail. HE EXISTED, since it was he that doubted He turned this into a theory: methodical doubt

Methodical doubt: rules/deduction Accept nothing that you can’t clearly identify Reduce (the problem) into smaller bits, so it can be solved Go from simple to more complex (deduction) Make your conclusions as complete as you can, assuring yourself to forget nothing.

Thought experiments Brains in a vat Ghost in a machine If all knowledge is available on the internet, than why would we go to school?

Again… There is nothing you can be sure of Reduce, reduce Look inside: dreams Math? Demon deceives us Only when I doubt, think, I exist. That I can’t deny. God does not deceive Start subjectivism: The ‘I’ as starting point (ratio)

Rationalism Reason rather than experience is the basis of all our knowledge

Revolution in thinking: We can explain the world using formulas Explain the universe – planetarium Franeker, Eise Eisinga Simple things can explain complex matters Observations: large -> telescope Small -> microscope Dissect a human body -> blood circulation system (Harvey) Philosophy was no longer serving the church.

Pineal Gland -Pijnappelklier/ epifyse Dualism: body and soul Thinking (the soul) = consciousness Distinct from the body Truth is in us the mind interacts with the body at the pineal gland Pineal Gland -Pijnappelklier/ epifyse

suggested the body works like a machine, that it has material properties. The mind (or soul) was described as nonmaterial and does not follow the laws of nature. Descartes argued that the mind interacts with the body at the pineal gland. This duality proposes that the mind controls the body, but that the body can also influence the otherwise rational mind, such as when people act out of passion. Most of the previous accounts of the relationship between mind and body had been uni-directional.