1. Indirect realism
Learning objectives: to understand the objection to indirect realism that it leads to scepticism about the nature of the external world.

2. The specification says you need to know…
Indirect realism: the immediate objects of perception are mind-dependent objects that are caused by and represent mind-independent objects. Issues, including: 1. it leads to scepticism about the ‘existence’ of the external world (attacking ‘realism’) ° responses (external world is the ‘best hypothesis’ (Russell); coherence of the various senses and lack of choice over our experiences (Locke)) 2. it leads to scepticism about the ‘nature’ of the external world (attacking ‘representative’ or ‘indirect’) ° responses (sense data tell us of ‘relations’ between objects (Russell); the distinction between primary and secondary qualities (Locke)) 3. problems arising from the view that mind-dependent objects represent mind-independent objects and are caused by mind-independent objects.

3. Problem 2: How can we know what the external world is like?
IR leads to scepticism about the ‘nature’ of the external world (attacking the idea that we perceive the world indirectly)

4. What is the difference?
Problem 1: indirect realism leads to scepticism about the ‘existence’ of the external world (attacking ‘realism’) Problem 2: it leads to scepticism about the ‘nature’ of the external world (attacking ‘representative’ or ‘indirect’) Read page 44 Lacewing and summarise problem 2 in your notes.

5. To provide a response to problem 2, John Locke distinguishes between primary and secondary qualities. We will look at this distinction and then look at how he answers problem 2 using it.

6. An Intelligent Alien
An intelligent alien lands on earth. The alien has a very different set of senses from the ones we use to navigate reality. He has a sonic sense like a bat, and an electric sense like a dolphin. He has no colour vision & can only see in black and white. When he touches objects his nerves and brain translate the touches into noises that he hears in his mind. The alien is about to examine some objects from earth to see what properties the objects have.
Written Task:
What would the alien write down as the real properties – properties the alien perceives of the mind-independent object – of the following:
A pound coin.
A cup of coffee.
A piece of sandpaper.
10 min activity. Then feedback.

7. Therefore there are two types of properties for physical objects.
Would the intelligent alien be able to discern the property of value of the pound coin?
What does this tell us about the properties of physical objects?
The example of the alien suggests that some properties of physical objects are more closely related to our senses than others.
Colour, smell, sound, taste and texture depend very closely on our five senses. Creatures without these senses would not be able to perceive these qualities.
Shape, size, motion, position and number don’t depend so closely on our senses. Creatures with very different senses could still perceive these qualities.
Therefore there are two types of properties for physical objects.

8. Primary and Secondary Qualities
Primary qualities:
Qualities that exists independently of our perceiving them. In simpler terms, it refers to properties like shape, size and motion, that don’t depend on our senses.
Secondary qualities:
Qualities that require a perceiving mind to perceive them i.e. experience of the senses. In simpler terms, it refers to properties like colour, smell and taste, that do depend on our senses.
A good way to remember this: primary qualities are in objects ‘primarily’ (before perceivers come along); secondary qualities appear only ‘secondarily’ (after perceivers arrive on the scene).

9. The distinction is most commonly associated with Locke, but many other 17th century scientists and philosophers made the distinction too.

10. In pairs….
Read through the excerpts and highlight/underline points that you believe are relevant in helping to understand/define:
What are primary and secondary qualities.
How they are distinguished from each other.
Make sure you have a different colour for each section. i.e. what is a primary quality will be underlined in red.
10 min activity.
A little bit further…..
If you have completed the above create an argument in standard form using the example of a red rose to illustrate how we perceive objects indirectly.

11. Locke – Essay Concerning Human Understanding, II, Chapter viii
The idea of heat or light, which we receive by our eyes, or touch, from the sun, are commonly thought real qualities existing in the sun, and something more than mere powers in it. But when we consider the sun in reference to wax, which it melts or blanches, we look on the whiteness and softness produced in the wax, not as qualities in the sun, but effects produced by powers in it.
Whereas, if rightly considered, these qualities of light and warmth, which are perceptions in me when I am warmed or enlightened by the sun, are no otherwise in the sun, than the changes made in the wax, when it is balanced or melted, are in the sun.
They are all of them equally powers in the sun, depending on its primary qualities; whereby it is able, in the one case, so to alter the bulk, figure, texture, or motion of some of the insensible parts of my eyes or hands, as thereby to produce in me the idea of light or heat; and in the other, it is able so to alter the bulk, figure, texture, or motion of the insensible parts of the wax, as to make them fit to produce in me distinct ideas of white and fluid.
Descartes – Meditation 6
And although in approaching fire I feel heat, and in approaching it a little too near I even feel pain, there is at the same time no reason in this which could persuade me that there is in the fire something resembling this heat any more than there is in it something resembling the pain; all that I have any reason to believe from this is, that there is something in it, whatever it may be, which excites in me these sensations of heat or of pain.
Feedback.

12. A good way to remember this: primary qualities are in objects ‘primarily’ (before perceivers come along); secondary qualities appear only ‘secondarily’ (after perceivers arrive on the scene).

13. Characteristics of primary and secondary qualities
Primary Qualities
Secondary Qualities
Explain how physical objects interact with each other.
Explain how physical objects interact with us.
Can be described precisely and mathematically.
Can’t be described with this precision.
Are ascribed to objects by science.
Are not ascribed to objects by science
Are (arguably) essential to physical objects
Are (arguably) not essential to physical objects
Exist independently of the perceiver, in the objects themselves.
(Arguably) Exist only in the mind of the perceiver and not in the objects themselves.

14. Read pages 44-46 on Locke and primary/secondary qualities
Read pages on Locke and primary/secondary qualities. How does Locke use the distinction between primary and secondary qualities to respond to the objection that indirect realism leads to scepticism about the ‘nature’ of the external world?

15. OK, so what does this distinction have to do with Indirect Realism?
Secondary qualities are what we perceive through sense data as they are mind-dependent properties of the object.
Task:
Use what we have learnt in today’s lesson and the image above to explain indirect realism. Refer to the distinction between primary and secondary qualities!
Helpful hint: Remember sense data is what we are immediately aware of in perception i.e. the colour and shape of the desk as I see it now. (the mental representation)

16. The secondary quality argument
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.

17. 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.

18. Read page Lacewing Explain how direct and indirect realist view secondary properties differently.

19. Homework Read pages 22 – 26 in the blue book
Make notes on how philosophers draw the distinction between primary & secondary qualities. They must be put into your own words!