Berkeley's denial of the distinction between primary and secondary qualities

Question

What does it mean to say that ideas are all that are real? How does Berkeley's denial of the distinction between primary and secondary qualities result in this claim? (This distinction itself is probably worthy of discussion. Think about Berkeley's example of why is it that we say the fire is hot, but the fire is not in pain?) In what way does Berkeley's philosophy not deny the reality of external existence?

Answer 1

(1) What does it mean to say that ideas are all that are real?

It means that anything that is real is an idea. In particular, it means that the real, apparently material stuff that we perceive all around us--including our own bodies--are not actually material objects even though they seem to be. Instead, these objects are really ideas, and for Berkeley these ideas exist in God's mind. This is how they can continue to exist even though we aren't perceiving them: God perceives them, and this maintains their existence and allows us to perceive them too.

(2) How does Berkeley's denial of the distinction between primary and secondary qualities result in the claim that ideas are all that are real?

Primary qualities refer to things like shape, which are supposed to be mind-independent qualities of objects. In other words, primary qualities are qualities that objects are supposed to have independently of how we view them. Secondary qualities, like color or taste, are not supposed to be mind-independent qualities of objects, but are rather qualities that we project onto things. For instance, the quality "red" that we perceive things to have isn't really a mind-independent quality of the object, but is rather just how we perceive it. The colors that "things have", then, are really just ideas in our minds; they aren't actual qualities of objects. Berkeley argues against this distinction by arguing that primary qualities are no less mind-dependent than secondary qualities are. Something's shape or length, for example, can look different to people perceiving it from different angles. A car looks quite big when you're right up next to it, yet it looks very small when you're up in an airplane. Berkeley thinks that these examples illustrate that primary qualities are just like secondary ones in that they are only ideas in our minds rather than actual, mind-independent qualities of external objects. Berkeley, then, would claim that all the sensible qualities of objects that we perceive--whether "primary" or "secondary"--are just ideas in our minds. I'm not entirely sure about this, but I believe that Berkeley also maintains that there's nothing more to external objects than the sensible qualities they have--take away these qualities and you have no external objects. So Berkeley's argument here looks something like this: all sensible qualities, whether primary or secondary, are ideas, and since external objects are just collections of sensible qualities, these objects are just collections of ideas.

(3) How does Berkeley's philosophy not deny the reality of external existence?

Although Berkeley argues that the external objects that we perceive--all the stuff that we perceive as being external to us--are ideas, he doesn't argue that they don't exist or might not exist because they are or might be mere creations of our own minds. For him, these external objects definitely exist, but they are not what they might appear to be--they aren't material things. They are ideas, but they aren't the mere creations of our own minds that have no real, external existence independently of our own minds. They are rather ideas in God's mind, which allows them to really exist externally to our own minds.