Can you trust your senses?

WHAT DO YOU KNOW?WHAT DO YOU KNOW?

AN INTRODUCTION TO SCEPTICISM

• Today you are going to learn something that will shock and surprise you. You will find it very difficult to believe. Most of you, in fact, will not believe it.

• Nevertheless it is true.

• Please spend a few minutes writing your answers to the following questions

• Where are you right now?

• How do you know?

• What is the year?

• How do you know?

• Who are you?

• How do you know?

• In fact, everything you think you know is a lie

THE TRUTH IS…..THE TRUTH IS…..• Your senses have been lying to you

• In fact, you are a brain floating in a vat of fluid in a laboratory. The year is 3577

• Your brain is wired to a computer that is controlled by scientists

• The computer sends electrical signals to your brain to make it believe it is receiving information from its senses

• All of the world around you, all of the people and all of your memories are in fact part of a computer programme.

DON’T BELIEVE ME?DON’T BELIEVE ME?

• What will you do to try and prove me wrong?

• I can understand that, it would be much too difficult for you to accept the truth.

• I am one of the scientists in the laboratory and I think what is being done to you is cruel. I am trying to help you see your real situation.

• That is why I’ve hacked into the programme to show you this slide show.

• I am going to show you a few things to try and prove to you that what you think is real, is in fact an illusion.

• 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

STILL DON’T BELIEVE ME?STILL DON’T BELIEVE ME?

• Can you remember any dream that you had recently?

• When you were having the dream, did you know that you were dreaming? Or did the dream seem real to you at the time?

• Most of the time, when we are dreaming we usually totally believe that we are awake

• Once we wake up, our dreams seem crazy, but at the time they feel real

• So how can you be sure that what seems like reality now is not in fact a dream?

YOUR SENSES LIE TO YOU ALL YOUR SENSES LIE TO YOU ALL THE TIMETHE TIME

• All of what you believe that you know about the world comes from the evidence of your senses – what you see, smell, touch, taste and hear.

• But your senses lie to you all the time.

• Let me show you. Look at the next picture and tell me which circles are moving…

• In fact, none of the circles are moving, it is a still image.

• Can you see the spiral in this next picture?

• In reality, there is no spiral, just a series of circles

• This next one probably feels as if its coming out of the screen at you

• Which letters are moving on this picture?

• Which way are the rollers moving?

• So you see, you can’t always trust what your eyes tell you

• The same is true of your other senses. They sometimes lie to you as well.

• So how do you know that your senses aren’t lying to your right now? Can you really trust your eyes when they tell you that you are in a classroom in a school in Burnham?

• How do you know that your senses haven’t been lying to you your whole life?

• As you know, light travels very quickly. But it still takes time.

• Because of this, when you look at the stars at night, you are not seeing the stars as they are, you are seeing the stars as they were. You are seeing a copy of the stars, almost like a film. Some of the stars that you can see in the night sky are probably no longer there

THE WORLD IS NOT AS IT THE WORLD IS NOT AS IT SEEMSSEEMS

You are effectively seeing the ghosts of stars

• The sun that you see is actually the sun as it was around eight minutes ago. For all you know, the sun might no longer exist

• In the same way, the screen that you believe that you are looking at now is the screen as it was a fraction of a second ago. Not only does the light take time to reach your eye, but it also takes time for your brain to process that information.

So, would you take the red pill or the blue pill?

Would you want to know the reality of the matrix?

Scepticism

• This lesson will be successful if you can– explain philosophical scepticism– Explain Descartes Cogito– Evaluate the strengths and weaknesses of the

Cogito

Big Question!Big Question!

• The point of view we’ve been talking about today is sometimes called ‘Global Scepticism’. This means that you doubt that ANYTHING you think you know is really true.

• What effect could global scepticism have on your life? Think Pair Share

Rene Descartes

• Was a 16th Century Philosopher, who used scepticism to establish the foundation of his beliefs.

• He used 3 stages of doubt to establish what he could be certain of.

Sometimes we can be deceived

• Is this pencil bent?

Dreaming

• http://www.youtube.com/watch?v=66TuSJo4dZM

• How can we know we are not always dreaming?

There is a demon who is always deceiving us

• So Descartes came up with the idea that the only thing we can be sure of is that– I think, therefore I am.

– What does this mean?

Scepticism

• This lesson will be successful if you can– explain philosophical scepticism– Explain Descartes Cogito– Evaluate the strengths and weaknesses of the

Cogito