Berkeley’s Three Dialogues Is there material substance? Does the belief in material substance lead to skepticism?

Hylas believes that matter exists and those who deny that matter exists are skeptics. Philonous denies that there is matter, and thinks the belief in matter leads to skepticism

Direct Realism Direct realism has two parts: Material objects exist unperceived Material objects are directly perceived On this view, there is no intermediary between us and the world, what we see, hear, touch etc, just is a part of the real mind independent material world

The pleasure/pain argument Extreme heat is a kind of pain Pain cannot exist unperceived Therefore, the immediately sensed extreme heat, is not independent of the mind. Similar arguments can be used for all direct objects of sense that are painful or pleasurable.

The perceptual relativity argument If I am directly aware of the temperature of the water, then the water is both hot and cold The water cannot be both hot and cold Therefore I am not directly aware of the temperature of the water Similar arguments can be made with colors, tastes, smells.

The primary/secondary quality distinction. Hylas gives up holding that all sensible qualities are in the objects. Primary Qualities: extension, figure, solidity, motion and rest Secondary Qualities: colors, sounds, smell, tastes, all qualities except the primary Only primary qualities exist in external objects.

An argument against the distinction: The perceptual relativity argument applies to both primary and secondary qualities It is impossible to conceive of a primary quality without a secondary quality ----For example, you cannot think of a shape, without also thinking of it as colored. The two sorts of qualities are necessarily conjoined. ----For example, you cannot think of a shape, without also thinking of it as colored. The two sorts of qualities are necessarily conjoined.

Whatever is inconceivable is impossible I cannot conceive of a shape without a color Therefore shape and color are necessarily connected. (its impossible to have shape without color)

What about tangible shape? We can get an idea of shape by touch Is this idea the same as that obtained by sight? Are there also tangible secondary qualities necessarily connected with tangible shape?

If spatial qualities cannot be understood independently of “secondary qualities” then this argues against Descartes’ claim that spatial extension, but not color etc. is essential to material objects