Ideas of Primary and Secondary Qualities

In my previous post I took a stab at explaining the primary-secondary quality distinction.

But this is only part of the story, and until you know the rest, Locke will leave you puzzled. (Well, he may leave you puzzled anyway, but hopefully less so once you know the full story!)

So now I'll attempt to finish the picture.

Specifically, I'm going to talk about our ideas of primary and secondary qualities. To begin, I remind you again to always distinguish the idea of a thing from the thing itself; the idea of X is one thing, X is another. Generally speaking, Xs have different properties than ideas of Xs. (Cats versus ideas of Cats--the former meow, the latter do not!) And--again speaking generally--whereas ideas of Xs are always mental entities (mental states), Xs are not. (Ideas of cats are things in the mind; cats are not.) [There are exceptions to the rule: for instance, when we are talking about ideas of Xs and ideas of ideas of Xs--in that case both the idea and the thing the idea is an idea of are mental; but I think you can see that the general point still stands.]

Well, applied to our present topic, this means we must distinguish at least four things:

1) Primary qualities (such as extension, shape, location, motion, number)

2) Secondary qualities (such as color, sound, warmth, cold, taste, scent)

3) Our Ideas of Primary qualities; and

4) Our Ideas of Secondary qualities

Let's think about items (3) and (4), starting with some examples. Using our X v. idea of X formula is simple enough. Our ideas of primary qualities thus include: the idea of extension, the idea of shape, the idea of location, the idea of motion, and the idea of number (I think here is this best understood as the idea of we have of how many of a certain kind of thing there are). Likewise, among our ideas of the secondary qualities are: the idea of color (and the ideas of particular colors: red, green, etc.), the idea of sound, the idea of taste, the idea of warmth, the idea of cold, the idea of scent, and so forth.

Well, those are the examples. But in the back of my mind I seem to hear Socrates making some remark about examples and definitions...

So let me try to say something more informative.

First, concerning ideas. We are following Locke's use of this term, not Hume's. If you like Hume's terminology, just substitute "perceptions of the mind" where I use "ideas". What are ideas, in Locke's sense? They are the immediate objects of awareness. Whatever you are directly aware of when you have a visual experience, a thought, a feeling--that is an idea.

We can say more. Ideas are mental entities. They exist "in the mind", and cannot exist without a mind. What does this mean? Good question, but I can gesture at what these guys are talking about by drawing upon scenarios portrayed in movies like The Matrix and Inception. What are people in the Matrix aware of? (In whatever sense it is true that they are aware of something.) Answer: Ideas. What are people aware of when they dream (or when they enter a dream, like the "extractors")? Ideas. Whatever it is one is aware of when one dreams (or has hallucinations), that is an idea. That very thing does not exist "in reality" (in the objective world), but only "in one's mind".

Now back to our examples. When you have a dream of an object with a certain size, shape, and location--an apple, perhaps--the particular size, shape and location of that object, as you are aware of these qualities in your dream, as they are present to you in your dream, are ideas of primary qualities. Specifically, they are ideas of a particular size, of a particular shape, and of a particular location.

Now consider the red color, the sweet taste, the fragrant smell, the cool feel, and the sound (crunch! [I like crispy apples]) you experience as you take a bite of the apple in your dream. These qualities, as you are aware of them in your dream, as they are present to you in your dream, are ideas of secondary qualities (Hume called them 'impressions'.)

I've used the example of a dreamt object (as opposed to an experience of an actual object) to help keep clear on the difference between the ideas of primary and secondary qualities and the primary and secondary qualities themselves--since there is no actual apple, there are no actual instances of the primary qualities of size, shape, and location, nor are there any actual instances of the secondary qualities of color, taste, scent, coolness, and sound.

One more point before I conclude this post. It is a point I've made before, but I reiterate it because it is easy to forget, and forgetting it leads to confusion. The primary and secondary qualities themselves are properties of objects and events in the world; they are not properties of mental states (ideas). Primary qualities are intrinsic properties of those objects (properties they possess "in and of themselves"); secondary qualities are also properties of the objects, even though objects possess them partly in virtue of the effects they have on other things. Ideas, on the other hand, are not properties of objects; hence, in particular, ideas of primary and secondary qualities are not properties of objects. They are mental states.

That's enough for now, don't you think? I hope this is making some sense.

But why is all this stuff about primary and secondary qualities, and our ideas of them, important? And why believe it?

Sounds like a topic for another post, doesn't it? :)

Now let's hear those questions and comments!