I. Philosophy after Descartes
A. At first, Cartesian rationalism thrived in philosophy
B. Especially in Britain, things started to take a more empiricist turn. With the growth of science, there was an increased focus on the nature of observation and use of the senses. This impacted philosophy as well.
C. "British Empricism": usually refers to three major figures
II. Locke on perception
A. Some things Locke borrows directly from Descartes
B. General model of perception. Example: flower
III. Berkeley's Life
IV. Berkeley's reaction to Locke
1. Accepted Locke's arguments that secondary qualities are ideas in the mind, but said they could be pushed further
2. Ideas cannot resemble things outside the mind.What could it mean to say that a color resembles something unperceivable? What could it mean to say that a feeling of touch resembles something intangible?
3. External objects cannot cause perceptions. How can something inert and material cause an idea in an active, immaterial mind or soul?
4. Without any of that, there is no reason to believe in material substances at all. In fact, the idea of them is incoherent. They are supposed to be matter, and thus substances that don't think, feel or perceive. But they are also supposed to have primary qualities, which are ideas . How can a substance that doesn't think, feel or perceive have ideas?
5. What are we left with? Immaterialism/idealism: the only things that exist are minds/souls and their ideas.
6. What is the flower then? Berkeley doesn't think that the flower doesn't exist. Instead, he thinks that it is just a collection of ideas or perceptions. As he says, Esse est Percipi. "To be is to be perceived." For objects of sense, their being is their being perceived by us.
V. Skepticism and Sensible Things
Dramatis Personae of the Three Dialogues: Hylas and Philonous
B. What do we sense? "Sensible qualities". These are listed on p. 11. It is concluded that there remains nothing sensible except for sensible qualities or combinations of sensible qualities.
C. Secondary Qualities do not exist outside the mind (Here Berkeley is largely repeating Lockean arguments)
1. Heat and Cold
3. Odors: perceptual relativity
D. The same arguments show that Primary Qualities also do not exist outside the mind
1. Extension (size) and figure (shape)
3. Solidity: perceptual relativity again
4. In general, so-called primary qualities presuppose extension, so once we acknowledge that extension exists only in the mind, it follows that they all do
VI. Object and Sensation
A. Hylas tries to make a distinction between two components of perception: the sensation and the object of sense
B. Philonous suggests that the distinction breaks down
VII. Material substance
A. Material substance as substratum
1. Hylas then suggests that there needs to be material substance to serve as substratum for all the sensible qualities to "inhere in" or "spread under"
2. Philonous responds
B. Philonous goes on the offensive. He gives his "Master Argument" as to why material substance is impossible. The very idea of material substance involves a contradiction.
1. The argument
2. This is a horrible argument. It commits what logicians call a "scope fallacy".
A. Hylas: if objects aren't "out there", why do we perceive them as outside or distant from ourselves?
B. Philonous: we don't actually perceive the distance itself. We just perceive different ideas and colored patches of different sizes, and we learn by experience to make predictions about ideas we'll have if we move around in certain ways.
A. Hylas: ideas resemble external things in the way that a picture resembles the original (example: Julius Caesar)
B. Philonous: the supposed original things that our ideas resemble: are they perceivable or not?
X. External things as cause of our ideas
A. Hylas repeats the Cartesian/Lockean picture of perception. External physical things bring about motion in the brain. This motion somehow causes ideas in the mind.
B. Philonous: The brain is just another sensible thing, and hence is a collection of sensible qualities, which are ideas, and thus exist only in the mind. How can one of the images in our mind be said to cause all the others?
C. Notice that Philonous' position in many ways solves the problem of mind-brain interaction that Descartes faced. Philonous suggests that there is no causal relation between "a motion in the nerves, and the sensations of sound or color in the mind." They might always go together, but one is not the cause of the other. What does cause our ideas? This turns us to:
XII. Berkeley's argument for the existence of God
A. Matter doesn't cause our ideas. What does?
B. Philonous suggests that it couldn't be us. Look at how marvelous and beautiful the world is. Look at how great and various the number of things are. Look at how regular and well-ordered the world is. Obviously, the reality of all these things cannot depend on my mind alone. But we've already concluded that they can only exist within a mind. Therefore, there must be an infinite mind, and infinite intellect in which all things exist. This, of course, is God.
C. God is the cause of my ideas of sense.
D. Notice how this argument is backwards from that of Descartes. Descartes appeals to God to prove things about the nature of his perceptions. Berkeley uses the nature of his perceptions to prove God. (Here we have part of the difference between empiricsm and rationalism.)
XIII. Secondary Cause, Instruments, Occasions
A.But even if God exists and is ultimately the cause of everything I sense, couldn't matter be a secondary cause? Philonous responds:
B. Couldn't matter still be an instrument or tool God uses in bringing about our ideas? Philonous responds
C. Couldn't matter still be the occasions of our perceptions. That is, God alone causes our ideas, but the presence/nonpresence of matter determines what sorts of perceptions and ideas God creates in us. This would explain the regularity and orderedness of our perceptions. Philonous responds:
XIV. Immaterialism contra Skepticism (end of second dialogue and beginning of third)
A. At this point, the entire Lockean picture has been dismantled. Nothing remains of the external objects or matter supposed by Locke and Hylas
B. Hylas still sticks to his belief in matter. He suggests that unless sensible things can be understood as things existing outside the mind, they have no reality at all.
C. Here we see how Hylas' positions leads to skepticism. For him knowledge is knowledge of matter, however
D. Philnonus charges Hylas with being irrational. He doesn't even seem to mean anything by "matter" at all. Yet, he'd sooner accept skepticism than to abandon the idea that if sensible things are real, they must exist independent from minds.
E. This very notion of matter--that sensible objects are not the very things we see and feel--is a bizarre invention of philosophers. No wonder people like Hylas and Descartes are pushed towards skepticism.
F. Philonous's position gets around skepticism
XV. Objections to Immaterialism and Philonous' Replies
(some are skipped)
O1: Suppose you were annihilated. Wouldn't that mean that everything you perceived would cease to exist. For that matter, don't the things you perceive cease to exist when you turn your head?
R1: They could still exist in some other mind. And since God always perceives everything, the objects of sense continue to exist with or without me, and regardless of where I turn my head.
O2: Isn't the doctine of Esse est Percipi contrary to common sense?
R2: Ask ordinary people and you'll find that they believe in those things and only those things perceived by sense. And they think what they see or feel are the very things themselves. They certainly don't believe in some philosophical material substratum that no one can see or feel.
O3: According to immaterialism, what could be the difference between "real" things and things formed in the imagination or in dreams?
R3: Well, it's true that all of these things are ideas. But there are differences. Things in dreams and imagination are dim, irregular and confused. They only exist in my mind. They are only perceiable by one sense. "Real things" are vivid and clear. They exist in other people's minds as well as mine. They are perceivable by more than one sense.
O4: Doesn't it sound weird to say that there are only minds or ideas?
R4: It may sound strange, but it doesn't mean anything strange. It just means that there are only things perceiving and things perceived.
O5. If God causes all our ideas, doesn’t that make God the author of murder, sacrilege, adultery and other sins?
R5. Even people like Descartes and others who invoke matter as secondary cause, matter or occasion have this same problem. It's no objection to immaterialism in particular. Moreover, it's not the ideas that constitute outward physical acts that are morally wrong. Sin is the internal deviation of the will from God's commands. We are responsible for our own volitions.
O6. If immaterialism is true, then aren’t oars that look crooked in water really crooked? And isn’t the moon really just a flat circle of a tiny diameter? Are people who think these things actually mistaken at all?
R6. Such people are not about what they actually perceive. Insofar as the oar is just a collection of ideas, it is in one sense really bent . The mistake comes in with the inferences they make from these ideas--by infering that the oar will still be bent if pulled out of the water or that if we were looking at the moon from a very different location that it would still look the same.
O7. If we get our ideas of pain from God, doesn’t that mean that God feels pain, and thus does not exist in a perfect state of being?
R7. It's true that God has to have some idea of pain. He understands and is aware everything, including pain. But this doesn't mean that God's idea of pain is the same sort of feeling that we have. God just directly knows what pain is. He doesn't need to perceive it or suffer it the way we do.
O8. Why would God deceive us into believing in matter if there is none?
R8. God hasn't deceived anyone. God would only be guilty of deception if God said that matter existed in scripture (which he didn't) or has made it so evident that no could help belieiving it. But the existence of matter is not made evident to all by God. The belief in matter is an obscure theory concocted by philosophers.
O9. If things are just certain perceptions, then how can the same thing be perceived so differently, for example, with the naked eye and with a microscope? Similarly, since we don’t have access to other people’s ideas, how can two people ever perceive the same thing?
R9. Technically, we're having different perceptions when we look at something with the naked eye and with the microscope. So in that sense, strictly speaking, we're seeing different things. But language has been constructed so that different ideas are collected together under a single name--otherwise we'd never get anywhere. And yes, strictly speaking, we only see our own ideas. Still, since my apple-ideas and your apple-ideas are similar, even identical, it is convenient to consider them the same thing for the sake of language.
Return to course homepage