On Tuesday 2/18/14 we recorded our episode on George Berkeley. Berkeley is the middle of the three "modern" (i.e. he lived in the early 1700s) empiricists that folks generally have to read in philosophy classes, the first being John Locke and the last being David Hume. We tried to cover the important parts of this tradition on our episode on Hume's epistemology, and I for one was happy to skip Berkeley on the grounds that his position is to my mind antiquated and crazy. But hey, our standards re. covering only what is "essential" have gone down a lot since then, and we have found on numerous occasions since then that the position of "idealism" has come up, if only as a bogey man, and now that we're (slowly) making our way further into the historically important metaphysical positions, it seems apropos to cover him now.
Idealism is the metaphysical position that everything that exists is an idea, and the quick formulation of this is that "it's all in your head." That would be solipsism, though, so let's amend that to "it's all in our heads," and it's that kind of position that an "objectivist" would be infuriated by: the idea that this table in front of us is somehow a shared delusion, that when no one is in the room with it, it ceases to exist. That kind of idealism, however, is not Berkeley's. For Berkeley, yes, the table is an idea, or more precisely a bundle of sensations that tend to go together in our experience, but when we leave the room, it's still there, as an idea: in the mind of God. He stresses that for a theist, this shouldn't be a crazy sounding position: all things rely for their existence on God, and doesn't it show off God's omnipotence more if He doesn't need a mechanism external to Himself to create things, but instead just thinks them up. As one further modification of the doctrine of idealism as "ideas are all that exist," for Berkeley (as for Descartes), when you have an idea, you of course have a thinker, a Spirit who has that idea. So his idealist ontology (the list of types of things that exist) has both ideas and Spirits in it.
None of this so far sounds very empiricist: empiricists think we know things only based on our experiences, that we don't have any non-empirical "intuition," any built-in knowledge or anything like that. But Berkeley, first in A Treatise Concerning the Principles of Human Knowledge (1710) and then in the book that we're reading, Three Dialogues Between Hylas and Philonous (1713), argues that his position really does come right out of our experience.
First, he follows Locke and (probably) Descartes in thinking that all we experience are our own ideas. In the dialogue, Philonous ("mind-lover") is trying to convince Hylas ("hyle" refers to mater or stuff) of Berkeley's position and first gives something like the traditional skeptical arguments against the idea that we actually do experience things in the world themselves. Dip one hand in ice and the other in hot water. Now put both hands in luke-warm water. One hand tells you "this water is hot" and the other hand tells you "this water is cold" (by comparison to where each hand previously was). Can the same thing (the water) be both hot and cold? No, so that means the degree of heat is not really in the water at all, but in our sensation. He does the same thing with color: the color of an object looks different in different lighting conditions, so what's the "real" color of the object? We might want to argue that it's the one in "normal" lighting conditions, but Berkeley thinks this choice of "normal" is too arbitrary. We normally think we see something more clearly up close, but when we look at it with a microscope, e.g. the color visible without the microscope is likely going to disappear altogether.
Philosophers like Locke distinguish secondary qualities like heat and color from primary qualities like shape and mass, because the latter can be perceived with more than one sense, and are in fact mediated by the secondary qualities, in that we tell what the shape or mass of something is using our sensations of color, of touch as we move our hand around the shape, by pressure when we lift the thing, etc. So you might think that secondary qualities are in our heads, and primary qualities are out in the world, are real. Though Berkeley acknowledges that these two kinds of qualities are different, they're still both ideas on his scheme, for the same kinds of reasons: we experience the shape differently in different circumstances, so the shape must be in our heads.
The obvious objection to this kind of phenomenalism is that it doesn't explain why you and I see the same thing, or why the table that was here is still there when I (or you) look back at it later (unless someone has moved it); it doesn't explain why science works. Well, Berkeley has an explanation for that: yes, he's proven (he thinks) that everything must be an idea, and since (obviously) these aren't my personal ideas in the way that an object I might summon up in my imagination is --I can't make these ideas come and go at my whim-- then they must be ideas in a mind that's beyond my mind, i.e. God's. He takes this as a one-step, irrefutable argument for God's existence, and you can see how it transforms his idealism from phenomenalism into, actually, a form of realism: objects exist apart from your or my or society's whims, and science is our way of investigating them. What explains regularities in nature, for Berkeley, is the regularity of God's thoughts, and the order that science finds indicates this underlying orderliness of God.
So why not say that fine, we experience only ideas, but that these ideas resemble material objects? Well, since this way of putting the problem posits that we never actually experience these objects, then we can't actually ever compare a material object to our idea of it to see if they match: all we ever experience are ideas, with the exception that we also (per Descartes) have an immediate experience of Spirit, in that we experience our own minds, and this experience opens us up to reason that other people also experience ideas, and that God as infinite Spirit could have ideas too. Apart from that exception for Spirit (other minds and God), everything Berkeley accepts is supposed to accord with strict empiricism: we only have the right to talk about, because we only know anything about, that which we can experience. "Matter," something that is supposed to underlie experienced qualities like shape and color, is something that Berkeley doesn't think we have any real conception of. Part of his empiricism entails that you can't legitimately abstract qualities away from your experiences and retain a real idea. So I can think about the "red" that this flower and that book have in common, but I can't really think about red in itself, not attached to anything. In the same way, Berkeley asks about that table you can conceive of with no one looking at it: can it exist? Well, if you're imagining it now, then it's not existing without any thinking about it going on, because you're thinking of it! You trying to abstract away from your thinking about it (or anyone thinking about it) from the table and imagine the "un-thought-of table" is just as illegitimate as you trying to imagine "red in-itself."
Of course, these arguments don't work very well, but they're fun to play with, and reading this book demonstrates well that not all kinds of idealism make science impossible. In fact, Berkeley thinks that it's the belief in matter that brings skepticism to science: as long as you believe that our ideas (what we perceive) are one thing and the world is something else, how can you ever be sure that your ideas correspond to the world? ...That we have any real knowledge at all? Berkeley claims to be sticking instead with common sense (if not common terminology) in saying that colors exist in objects and aren't something we impose on them, that the table really is here and is not something other than these properties which my senses apprehend. All of our sensations are by definition accurate, and when we make a mistake, like we think the stick in water is bent and so expect it to be so when we pull it out but are then surprised, then the mistake is in being wrong about which kinds of sensations go together. That's what science, on Berkeley's view, is about: it's about discovering those regularities in sensation, so that we can then make the predictions that allow engineering to work or allow us to predict if that comet is going to hit the earth or not.
Berkeley thinks that it's philosophers, in their insistenceÂ thatÂ Matter underlies and is the truth behind the sensible properties, who have tried to pull us away from common sense and towards dreaded atheism, thinking that the machinery of the universe could have its own internal causality and order, when clearly in our experience it's only Spirits that are active, and ideas are only passive, passing before our eyes in succession. It might seem weird (and nearly Humean) to say that in the case where a billiard ball hits another one, the first doesn't cause movement in the second, but to posit some active force within an object goes way beyond, for Berkeley, what we actually experience, whereas you do have the experience of manipulating ideas in your mind, making them come and go in your imagination at will, so Berkeley thinks that it better accords with our experience to say the first billiard ball is an idea of God that we then have too, and the second ball is likewise such an idea, and that it's God that creates the orderly succession whereby one hits the other and creates patterns of motion in ways that scientists can study.