1. Bullet Point on Whiteboards!
Explain why indirect realism may lead to scepticism about the nature of the external world, and one potential response to this problem (12 marks).
Add in mark scheme for 12 markers here.

2. Homework
“Given what we’ve covered over the last few lessons, do you think it’s possible for us to know anything about the external world?”
Due: By next lesson
Add in mark scheme for 12 markers here.

3. IDR Issues 2
What can you tell me about the subject of the picture, using only what you can see in the picture?

4. IDR Issues 2
What if I told you that neither of these people exist. That they are CGI (top) or paintings (bottom) and are composites of various people. Is there anything about your perception / sense data that could give it away? Why might this relate to Indirect Realism?

5. IDR Issues 2
A second major issue with IDR, and one that goes a step further than the previous problem, is the fact that proving the existence of an external world seems impossible. If all we ever see is sense data that is mind-dependent, there seems no categorical way to prove there is a physical mind-independent world at all. Perhaps we are effectively ‘living a dream’.
This is an issue posited by the Philosopher Descartes (again very important) who discusses the idea of an evil demon controlling our lives.
This demon could have control of our souls or minds and in some sick twisted game is giving us the impression that we are perceiving a real, existing world, when in fact we are not.
Descartes (initially) sees no real way of solving this issue.

6. Scepticism – Doubting something that we may usually claim to know.
IDR Problems 2
This issue is usually summarised as: “Scepticism about the existence of mind-independent objects.”
Once again both Locke and Russell accept that this is a major hurdle for Indirect Realism, neither believe that they can prove the existence of the external world conclusively.
That being said, both philosophers give reasons as to why they think the existence of the external world is overwhelmingly likely.
Scepticism – Doubting something that we may usually claim to know.
Often used in Philosophy as a method of testing the validity of knowledge claims.

7. Indirect Realism Weaknesses 2
Lesson Objective:
Examine how Indirect Realists may respond to scepticism about the existence of the external world.
Discuss some of the criticisms of these responses.

8. Response 1: Locke – Involuntary Nature of Perception
“If at noon I turn my eyes towards the sun, I can’t avoid the ideas that the light or sun then produces in me.” This suggests:
“They must be produced in my mind by some external cause.”
What colour is the sun in the picture? Can you control the colour sensation it produces in you? Can you avoid the colour sensation it produces in you?
The first response from Locke is the involuntary nature of our perception. By this he means that sense experiences cannot be controlled the way remembered experiences (for example) can be.
We can, using our imagination, conjure the smell of a rose, or the taste of sugar and we can control precisely how strong or weak these remembered sensations are.
We cannot do this for sense experiences, there is no way I can avoid the idea of yellow the image of the sun produces in me. Nor can I control how strong or weak that sensation is. Since I have no control over these sensations, the source of them must be external to me.

9. Counter – Dreaming
As a counter to Locke’s argument we may use the concept of dreams, in which we often have no control over our experiences (if we did nightmares would never occur). But we would surely not say that dreams come from somewhere / something external to us? This would seem to suggest that Locke is mistaken in his claim that an involuntary sensation or experience must be externally caused.
Locke however replies that a dream of being on fire is very different than actually being on fire, and produces an entirely different sensation within us (how many people have actually been in pain during a dream?). Even in your worst nightmare, any pain you feel can’t be compared to the real thing.
Since waking life is significantly more “vivid” than our dreams in the sensations it causes, we can assume there must be some “real world” behind it.

10. Counter-Response – Locke
If our dreamer wonders whether the glowing heat of a glass furnace is merely a wandering imagination in a drowsy man’s fancy, he can test this by putting his hand into it. If he does, he will be wakened into a certainty – a greater one than he would wish – that there is something more. - Locke

11. Response 2: Locke – Coherence of Senses
A second response from Locke is a reiteration of something we’ve already discussed – primary properties of objects (and thus reality) can be perceived by more than one sense. Due to this we should be able to say with some confidence that the object really possesses these properties and, by extension, exists.
If this was NOT the case it would be an incredible coincidence that two very different senses (like touch and sight) agreed about the geometric properties of a particular object if those objects did not in fact exist or had no such properties. Surely it’s just easier to accept the object exists.

12. Response 2 (Development): Cockburn – Learning Connections
Why?
Well sight is nothing like touch! Sound is nothing like taste! Smell is nothing like sight!
So if these senses, that do not resemble each other in any way, not only back each other up in their perception of the world, but correlate in a predictable fashion, then we have good reason to suggest there is something behind it!
After all, why would we be able to predict these events occurring if there wasn’t something independent behind it? If our perception was entirely mind-dependent? Surely each sense would then just change independently of each other?
If I heat up a metal ball, I can predict it will change colour, I also know it will burn when I touch it.
Similarly, if I turn over a cube in my hands (touch), it’s shape might sometimes resemble a hexagon and sometimes a diamond, the shadows and lighting on the outside of the cube will also change in accordance with it’s position (visual). We might then accept that if we watched these changes enough we would know what to expect.
The very fact these changes in one sensation (touch) seem to correlate with changes in another sensation (sight) in a consistent, predictable way suggest that these must be a law-like reality behind our perceptions.
Catherine Trotter Cockburn ( ) develops this response from Locke. She argues that it’s not just the fact that multiple senses confirm the properties (and thus existence) of external objects, but the fact that we can learn and predict connections between these properties that backs up their existence in reality.
If I heat up an iron ball what changes would you expect to happen?
If you touched a glowing red iron ball what would you expect to happen?

13. Counter: Dreams! (Again)
We know our minds can produce scenarios in which our senses correspond to one another and behave in predictable ways, we do it all the time when dreaming. Dreams, as we have already stated, are not based on some external reality but are mind-dependent - so surely this shows that Locke and Cockburn have not done enough to prove the existence of an external world? We could just be in a consistent illusion.

14. Russell: Best Hypothesis
What possible causes can you think of for our experiences (apart from the existence of a physical world)?
Surely we might say, the existence of physical objects is simply a better, simpler and stronger explanation than these options?

15. Russell: Best Hypothesis
I can explain why the apparent apple I hid in the drawer can be found again when I return to eat it, if I suppose that apples actually exist as independent objects and thus persist when no-one is observing them. If I leave the apple in the drawer and forget about it, it does not vanish from existence, but continues and may later reveal itself to be rotting, a change independent of my mind! Russell accepts that some of the other explanations we identified may be possible, but he believes that none as effective when it comes to explaining our experiences as the existence of an external world. It is the best hypothesis.

16. Russell: Best Hypothesis
Our instinctive belief that there are objects corresponding to our sense-data… does not lead to any difficulties, but on the contrary tends to simplify and systematize our account of our experiences, there seems no good reason for rejecting it. We may therefore admit – though with a slight doubt derived from dreams – that the external world does really exist, and is not wholly dependent for its existence upon our continuing to perceive it. - Russell

17. Summary
Explain why Indirect Realists might have an issue when it comes to the existence of the external world.
Identify responses from Locke including:
Involuntary nature of sense experience.
Coherence of senses (along with Cockburn’s development of the idea)
Identify responses from Russell including:
External world as the best hypothesis.
Consider criticisms of these responses and whether they can be sufficiently dealt with.
Do you think the philosophers have managed to successfully argue for an external world?

18. IDR Weaknesses 2 - Summary
Lesson Objective:
Examine how Indirect Realists may respond to scepticism about the existence of the external world.
Discuss some of the criticisms of these responses.