1. BERKELEY AND IDEALISM Strange to claim there is an external world;
Inconceivable that mind independent
matter causes our experiences
EMPIRICISM
Realism entails a gap
Between appearance and reality
Objects are families of ideas, so
there is no sceptical gap
SCEPTICISM
God is required as the (only) source of
the stable families of sense experiences
which constitute objects
God creates a world in which we are not
victims of the sceptical gap
GOD

2. The Road to Idealism To be is to be perceived.
Idealism is thesis that all our experiences are experiences of mental representations.
There is no world of material, physical objects as we ordinarily think of them ‘out there’ in the world and which cause our beliefs, perceptions, feels and so on.
Material objects are to be understood as families of experiences.
There exist no objects independent of the mind…
…except God (according to Berkeley)

3. Berkeley’s Reasoning
George Berkeley ( ) is committed to empiricism.
Big problem with the primary – secondary property distinction.
The qualities of an object taken all together seem to be equally mind-dependent.
It is only if physical objects are collections of ideas we experience in perception that we have any empirical evidence for their existence.
Radical re-thinking of what we mean by ‘physical object’.

4. …Principles of Human Knowledge (1710)
If knowledge is grounded in experience (empiricism), then we have no perceptual experience which grounds the claim that there exist mind-independent objects.
Why?

5. What can we conclude from our experience of the world?
We immediately or directly perceive ideas (e.g. beliefs, memories, sensations).
Your experience is your perception of qualities or properties.
The vast majority of collections of sensory perceptions occur with regularity and stability.
They come to be named, ‘and so reputed to be one thing’, such as an apple or tree.
Furthermore…

6. There is something distinct from what is perceived
There is something distinct from what is perceived. This is the mind or soul or myself. (Principles 2)
and
One’s ideas (e.g. beliefs) cannot exist except in the mind perceiving them. (Principles 3)

7. Their essence is to be perceived: esse est percipi.
Arriving at Idealism…
It now follows that if objects are collections of qualities and qualities are sensible ideas, then objects are sensible ideas.
Their essence is to be perceived: esse est percipi.
Nor is it possible that they should have any existence out of the minds that perceive them. (Principles 3)

8. Idealism is shocking.
But no scope to allow objects a perception-independent experience.
Objects are combinations of perceptions. No perception can exist unperceived. (Principles 4)
The notion of mind-independent existence is a contradiction. (Principles 5)
God is the source of orderly sets of sense experiences.
God ensures that objects exist when unperceived by no-one. (Principles 6)

9. The Master Argument (Three Dialogues 1713)
Everything is mind-dependent because the very attempt to conceive of something mind-independent is impossible.
In conceiving of it, you involve your mind.
Think of something…
Problems with Idealism?

10. Idealism is absurd. Samuel Johnson kicked a nearby stone and said, ‘I refute it thus!’
But what does this establish?
Kicking the stone establishes Idealism as well as Realism. Visual stone experiences are followed by tactile stone experiences.

11. It is expensive.
Instead of the world being the source of our experiences, we have to suppose God is.
How can I be sure God exists?
Wouldn’t God create a world in which the simple, commonsense answer (it’s the world causing my perceptions, Dummy!) is the right one?

12. How to explain dreams, error and illusion?
No problem – wild or random sequence of perceptual experiences in relation to well-ordered experiences we associate with veridical perceptions.
Explain the sense in which a misperception is false in terms of what one can say about the object in ordinary circumstances.

13. It is confused. Master Argument runs together two thoughts:
(1) You cannot conceive of anything without conceiving of it.
(2) You cannot conceive of anything unconceived.
(1) is trivially true.
(2) is false.
I can think of a world in which there are no minds. Just because I am thinking of it, I am not involved in it.

14. It leads to solipsism.
How can I be sure that there are other minds if all I experience are ideas?
Berkeley – Minds: esse est percipere (to be is to perceive). But, how can one know there is more than one’s own mind?