1. The secondary quality argument for indirect realism
R1. When I look at a rose, I see something that is red.
R2. The red thing cannot be the rose itself (since redness is a secondary quality which exists in the mind of the perceiver rather than the objects we perceive).
IC. So it must be a mental image of the rose – a sense datum.
C. But this means I see the rose indirectly, by seeing its sense-datum- in which case direct realism is false.

2. In a nutshell
Indirect realism, through primary & secondary qualities, develops a ‘two-world’ view of perception.
World No. 1 = the world as it really is. Objects with primary qualities obey the laws of physics here in a sense-less world i.e. no colour, taste or smell.
But it is this world, in conjunction with our perceptual system, that causes us to perceive ‘World Number 2’.
World No. 2, the world we directly perceive, is a representation of World No. 1, the world as it is.
Written task:
Create an analogy to help explain the distinction between primary and secondary qualities and how it explains how we perceive the external world.

3. How convincing is this distinction?
Is it really possible to imagine an object with no secondary qualities? Can you really imagine an orange as colourless, odourless and without texture?
They discuss – I take feedback and perhaps do a spider diagram.

4. Objections to indirect realism
Learning objectives:
To understand the objection that indirect realism causes scepticism about the existence of the external world
To begin to evaluate indirect realist replies to it

5. Problem 1: How can we know there is an external world?
Indirect realists say that all we ever perceive is sense-data.
Sense-data is mind-dependent.
So how can we know whether anything exists beyond the mind?

6. Problem 1: How can we know there is an external world?
See Russell ch. 2, last para. on page 8 (to half way down p.9)

7. Can you answer Problem 1 for indirect realists
Can you answer Problem 1 for indirect realists? How can we know there is an external world, even though it is perceived via sense-data?

8. Can you answer Problem 1 for indirect realists
Can you answer Problem 1 for indirect realists? How can we know there is an external world, even though it is perceived via sense-data?
Similarity between different sense-data suggests it comes from one thing.
It makes more sense to say there is a stimulus.
There are changes to physical matter when we’re not perceiving it (e.g. decaying banana). Makes more sense to say it changed whilst not being perceived.

9. Russell’s first response
Read the text from ch. 2, p.9 (2nd half)

10. Russell’s first response
People perceive the same thing.
What is his concern with this reason?

11. Russell’s preferred response
Look at me.
Close your eyes
Look at me again.
What’s the best explanation for our sense-data?
Physical objects existing or not existing?

12. Russell’s preferred response
See last para. on p.10- half way down p.12

13. Russell’s preferred response
Summary: Saying that there is an external world (including other minds) is the best hypothesis.

14. Locke’s two responses
Try not to think about a crocodile.

15. Locke’s two responses
See page 42 Lacewing.

16. Locke’s two responses I can’t choose my sense-data.
My sense-data gives me a coherent picture.

17. To what extent are Locke and Russell’s replies helpful in relieving us from scepticism about the existence of the external world? Read of Lacewing and write a half page long answer to this question

18. Learning objectives
To recap the distinction between primary and secondary qualities.
To evaluate the extent to which the distinction answers the objection to indirect realism that it leads to scepticism about the nature of the external world.

19. Problem 2: How can we know the NATURE of the external world?
Summary on your work sheet

20. Response 1: Locke on primary and secondary qualities
Read through your sheet

21. Write down an example of a primary quality of the apple
Write down an example of a primary quality of the apple. Write down an example of a secondary quality of the apple.

22. How do you know the shape is a primary quality?

23. Would the apple still roll off the desk if no one was perceiving it
Would the apple still roll off the desk if no one was perceiving it? What does this tell us about shape? Would its colour still be having effects if no one was looking at it?

24. Evaluation of Locke’s distinction
How clear is he?
Do you agree there is such a distinction?

25. How does the distinction help defend indirect realism?

26. How does the distinction help defend indirect realism?
The subjective view of secondary qualities can be used to defend indirect realism – we don’t perceive the world directly.

27. How does it answer problem 2?
Problem 2: Indirect realism leads to scepticism about the nature of the external world (what it is like).

28. How does answer problem 2?
Primary qualities are accurate reflections of reality… so SOME of our perceptions represent the world.
The world of appearances (of secondary qualities) is a representation of the world of reality (of primary qualities).
What’s the difference between representing and resembling?

29. What would an indirect realist say?
If a tree falls over in a forest, and no one is there to hear it…
…does it make a noise?
Use primary and secondary qualities in your answer.

30. Explain why for Locke, extension is a primary quality. (5 marks)

31. Learning objectives
To know Berkeley’s critique of the primary / secondary quality distinction
To know Russell’s response to issue 2
To evaluate whether indirect realism does lead to scepticism about the nature of the external world.

32. Starter / recap
Does this support the indirect realist’s case for secondary properties?
Why / why not?

33. How does the distinction answer problem 2???
What’s the difference between representing and resembling? Remember the OS map analogy.
Our secondary qualities _r________ but don’t _r__________ reality.
Primary qualities on the other hand… ?

34. Summary
Criticism: On indirect realism, how can you ever know the nature of the external world when all there is is sense-data?
Reply: We do have a true resemblence of the world via our perception of primary qualities.

35. Evaluation of the distinction btwn primary & secondary qualities
Is the distinction supported by modern science?
Can you really imagine something with its secondary qualities removed? Try to imagine a colourless, odourless, silent apple.

36. Is the distinction supported by modern science?
Think of what science has to say about:
Light
Sound
Heat

37. Bishop Berkeley (idealist)
See top Hodder p.38.

38. Berkeley’s criticism of the distinction
See top Hodder p.38.

39. Extension of arg. from perceptual variation
Different animals perceive time differently.
How could this be used to reply to the indirect realist’s point about primary vs. secondary qualities?

40. 1) Indirect realism
2) Issue: How do we know the nature of the external world?
3) Response: Distinction btwn primary and secondary.
4) Criticism of the distinction from Berkeley.

41. Extension of arg. from perceptual variation
Different distances affect our perception of shape and size.

42. Extension of arg. from perceptual variation
Different animals perceive size differently.
Didn’t your mum used to look giant?

43. Berkeley: Problems arising from the view that mind-dependent objects represent mind-independent objects
Optional / if time:
See the text from Berkeley (40-1)
Arguing against the ‘theory of resemblance’ in indirect realism (e.g. Locke)

44. Russell’s response to problem 2
Sense-data tells us relations btwn objects.

45. Russell’s response to problem 2
Find 2 objects of the same colour in this room.
Can we know that they are the SAME colour?

46. Does Russell’s response mean our senses represent the world?
Does a paint-by-number drawing look like the finished product?

47. Back to Berkeley: Problems arising from the view that mind-dependent object represent mind-independent objects
“What connection is there between a motion in the nerves, and the sensations of sound or colour in the mind? Or how is it possible these should be the effect of that?” (45)

48. Back to Berkeley: Problems arising from the view that mind-dependent object represent mind-independent objects
I think Berkeley’s criticism can be used as a reply to Russell’s response to scepticism that the external world is the best hypothesis. Given this un-answered problem, it is not clear that it is a more likely hypothesis.

49. What’s your conclusion?
If indirect realism is true, I think you can / can’t know the nature of the external world because…

50. Homework: Complete an essay plan.
15 marks Do we perceive the physical world directly? Due Wed Write down args. for and against. Draw on everything so far in ‘perception’.

51. Do we perceive the physical world directly?
Yes – perceive it directly
No – perceived indirectly

52. Do we perceive the physical world directly?
Yes – perceive it directly
No – perceived indirectly
Replies from direct realism
Common-sense
How can something mental represent something physical?
Indirect realism results in scepticism.
Berkeley: Yes – redefines ‘physical object’ as bundles of ideas.
Args against direct realism, e.g. time-lag Demonstrate sense-data
Distinction between primary and secondary properties shows that we do know the nature of the world, but not directly and not entirely representatively.