Ok, folks, here's your space to discuss Goodman's New Riddle of Induction.
Very briefly, the problem Goodman identifies is that any set of observations can justify any prediction about the future whatsoever, in which case, no set of observations really justifies any prediction at all.
The argument runs as follows. For any predicate, P, for which you have observed n positive instances--and hence expect P to be true of the n+1th instance--it is relatively straightforward to construct another predicate, P*, such that the n observed positive instances of P are also positive instances of P*. In which case, one can equally well expect P* to be true of the n+1th instance. However, P* is defined such that the n-1th instance cannot be both P and P*. Furthermore, we can repeat the reasoning, coming up with predicates P**, P***, etc., so that the n+1th instance will have any property at all. So, the n instances provide no more reason to expect the n+1th instance will be P than it does to expect P*, P**, P***, etc. In which case the n instances provide no reason to expect anything in particular.
That's the general formulation of the argument. It is easier to follow using the (now classic) example of the predicate "grue". An object is grue, recall, just in case it is either observed by some date t and green or unobserved by t and blue. Now, all emeralds observed by this date (whenever you're reading this) have been green, and using induction in the familiar way, we expect then next observed emerald to be green. But, having just defined "grue", it is clear that every observed emerald has also been grue. So, using induction in the familiar way, we should expect the next observed emerald to be grue. But, if we treat the time at which you--gentle reader--read this as t, then if the emerald is grue, it will be blue, not green. So the emeralds we have observed to this point provide no more reason to expect the next observed emerald to be green than grue--hence, blue. Furthermore, we can define predicates "gred", "grorange, "grellow", "grurple", etc. such that, by parity of reasoning, we have just as much reason to expect the next observed emerald to be red, orange, yellow, purple and so on. It follows that we really don't have any reason to expect the next observed emerald to be any particular color.
But of course this is absurd. Emeralds we have observed to this date do give us reason to expect the next to be green, and they give us much more reason to expect this than to expect the next emerald to be blue, red, orange, etc. (Nor do they provide reason to expect the next observed sapphire to be green, or blue, etc.--but this is a further development of Goodman's argument.) That is why Goodman's New Riddle is a paradox: an unacceptable conclusion reached from apparently acceptable premises via apparently acceptable reasoning.
The challenge is to come up with an explanation of why past observations of emeralds justify our expectation that the next will be green, rather than blue (etc.). That, it turns out, is surprisingly difficult to do.
Saturday, February 26, 2011
Sunday, February 20, 2011
The Copy Principle (aka, Hume's Sword)
The Copy Principle is David Hume's version of the old empiricist slogan, "Nothing in the mind that is not first in the senses" (Locke's "Tabula Rasa"). [Aside: it is more accurate to treat this as an anti-nativist slogan, but many empiricists have in fact accepted some claim along these lines, so we'll ignore the inaccuracy for the time being.]
Specifically, Hume thought that every idea we have (indeed, every idea we could have) is either (a) a copy of some impression or (b) constructed wholly from ideas that are copies of some impression.
Two notes: First, remember that we're talking about Hume here, so in this context the term "idea" refers to a subset of, for instance, Locke's Ideas. Here, "idea" means, roughly, concept or thought.
Second, I assume that Hume did not think that the Copy Principle just happened to be true of all of our ideas--I take it that he thought it was true of any idea we could, in principle, have as well.
Hume used the Copy Principle to discover the limits of what the human mind could meaningfully think. For if one cannot, at least in principle, trace an idea back to the impressions from which it was copied, then it was not a meaningful idea at all. At best, it is just a copy of some sound we have heard. Since meaningful thoughts can be built only from meaningful concepts, all meaningful thoughts are wholly composed of ideas that can be, in principle, traced back to impressions.
Using the Copy Principle, Hume argued that traditional metaphysics (of the sort offered by, for instance, Rene Descartes) was littered with meaningless concepts, concepts such as Cause, Substance, and Self, which could be traced to no impression. Philosophy, insofar as it deals in meaningful thought at all, must be confined to experience (or what can be "constructed" from things we have experienced).
The Copy Principle is a substantive and important thesis. What do you think of it? Is it plausible? Can you think of counterexamples? Where does Hume get the principle? What reasons does he offer for it? (Think of "Hume's Fork" here, and think about on which prong the Copy Principle might be found.) And how are we to assess Hume's use of the Copy Principle against apparent counterexamples? Is there any non-question begging way to use it?
Specifically, Hume thought that every idea we have (indeed, every idea we could have) is either (a) a copy of some impression or (b) constructed wholly from ideas that are copies of some impression.
Two notes: First, remember that we're talking about Hume here, so in this context the term "idea" refers to a subset of, for instance, Locke's Ideas. Here, "idea" means, roughly, concept or thought.
Second, I assume that Hume did not think that the Copy Principle just happened to be true of all of our ideas--I take it that he thought it was true of any idea we could, in principle, have as well.
Hume used the Copy Principle to discover the limits of what the human mind could meaningfully think. For if one cannot, at least in principle, trace an idea back to the impressions from which it was copied, then it was not a meaningful idea at all. At best, it is just a copy of some sound we have heard. Since meaningful thoughts can be built only from meaningful concepts, all meaningful thoughts are wholly composed of ideas that can be, in principle, traced back to impressions.
Using the Copy Principle, Hume argued that traditional metaphysics (of the sort offered by, for instance, Rene Descartes) was littered with meaningless concepts, concepts such as Cause, Substance, and Self, which could be traced to no impression. Philosophy, insofar as it deals in meaningful thought at all, must be confined to experience (or what can be "constructed" from things we have experienced).
The Copy Principle is a substantive and important thesis. What do you think of it? Is it plausible? Can you think of counterexamples? Where does Hume get the principle? What reasons does he offer for it? (Think of "Hume's Fork" here, and think about on which prong the Copy Principle might be found.) And how are we to assess Hume's use of the Copy Principle against apparent counterexamples? Is there any non-question begging way to use it?
Saturday, February 19, 2011
Reflections on the Primary-Secondary Quality Distinction, and Our Ideas of Them
In previous posts, I've offered explanations of the Primary-Secondary Quality Distinction and our Ideas of Primary and Secondary Qualities.
But now it's time to scrutinize these ideas (if you'll permit the pun!) a bit.
In particular, I want to consider:
(1) Why should believe any of this?
(2) Why is it important or significant?
Let's start with (1). To make progress on this question, I think we'd better distinguish a number of more specific questions that are mashed together in (1). Here are some of the more specific questions we might ask:
(I) Why should we believe that there are any Primary and Secondary qualities, as those qualities have been defined?
(II) Granted the definitions of Primary and Secondary qualities, why should we believe that the examples given of each kind really are instances of those kinds? In particular, why believe that color, sound, scent, etc. are Secondary qualities? Why not suppose they are Primary qualities?
(III) Why should we believe that our Ideas of Secondary qualities do not resemble any quality in objects?
There other questions we might list here, but the above is plenty for this post. Having noted question (I), I'm going to set it aside--I think it loses much of its interest once we've answered (II) and (III). I'm going to begin with question (III), since I think question (II) is easier to answer once we've answered question (III).
So, why should we suppose that our ideas of secondary qualities, such as color, sound, taste, smell and so forth do not resemble any quality in the object? I'm going to focus on the case of color for two reasons: first, it will simplify the discussion; second, it is the most controversial example (and so, if we can make the case with respect to color, we can make it for the other qualities as well).
It is important to remember that your idea of color--or, to be more precise, your idea of a specific instance of a specific color, e.g., your idea of the color of the apple (or whatever) you are seeing right now--is the color as you are currently aware of it; the quality apparently "out there" on the apple. That is your "idea of color". It isn't a very natural usage these days.
Indeed, it isn't a very natural think to think, is it? After all, isn't that color "out there" on the apple just the property red? Well, not according to advocates of the view we are discussing. According to them, the apple as it is in itself, apart from any particular way of experiencing it, isn't colored (in the way we usually think of things as being colored) at all.
One reason is simply that appeals to color, as such, do not appear to play any essential role in explaining anything about how objects interact with other objects. Sure, we appeal to color in everyday explanations--"Why did you buy that shirt?" "I liked the color"--but when we want to get technical, when we want a full explanation, appeals to color drop out of explanations in favor of talk of wavelength distributions, behavior of electrons, and neural activity. (I am not claiming that we can explain everything about color perception, by the way!) If we take Ockham's Razor seriously, we shouldn't believe in properties that play no role in our explanations, then we shouldn't believe that color is a surface property of objects (notice that I am not quite claiming that we shouldn't believe in color at all).
A second argument is this. All object-surface we perceive as colored are, ultimately, composed of atoms. But atoms, of course, are not colored. It is, furthermore, difficult to see how a colored surface could be built up out of ultimately colorless parts. So object surfaces aren't really colored. They simply appear colored because of the way they affect us (via the light they reflect--light which is not itself colored either). Strictly speaking, this argument commits the Fallacy of Composition. Still, insofar as it really is difficult to see how to make a colored surface from colorless parts, this argument creates a challenge for anyone who would maintain that color is a real property of surfaces of objects.
I suspect that most people who doubt that color is a property of objects are persuaded by some version of an argument that we can the "Argument from the Contingency of Color Experience". It goes something like this. The way we experience the color of an object is dependent upon three things: the character of the surface of that object, the character of the light reflected off of it, and the character of our perceptual systems. Change any one of these enough, and the object will appear to have a different color. (Of course, there are problem cases even here: objects that appear black; cases where there is no surface at all--the night and daytime skies; films; and colors of light sources, but let's set those aside for now.) However, it seems to be a contingent fact (a fact that might have been otherwise) that we have the perceptual systems we have, and that the light in our environment has the character it has. Moreover, had we lived in an environment with different ambient light, or had we developed different perceptual systems, we would have different beliefs about the colors of objects--and these beliefs would have seemed perfectly natural to us (as natural as our actual beliefs seem). In light of this, it can seem to quite unlikely that we just happen to (a) have the right sort of perceptual systems and (b) live in a world with just the right sort of ambient light so that the true colors of objects are revealed to us. Why should both (a) and (b) be so, given that things (it seems) could have been otherwise? Our inability to explain this can make our ways of experiencing the colors of objects seem quite contingent--a kind of historical/galactic accident--and this, in turn, can undermine our confidence that we perceive the "true colors" of objects. If you combine this line of reasoning with the arguments offered in the previous two paragraphs, skepticism about the view that objects are colored can begin to seem quite plausible.
Other arguments could be offered for the view that objects are not really colored in the way we ordinarily think they are, but I think I have said enough to convey the overall drift of the arguments.
Now let's recall the point of offering these arguments: it was to answer question (III), above. I think we can see that the arguments offered provide an answer to that question. For if we accept that objects are not colored in the ways we perceive them to be colored, then it follows that our Ideas of Secondary Qualities do not resemble any property in those objects.
Now let's turn to question (II), which is relatively easy to answer at this point. If you accept that no property in objects resembles any of our Ideas of Secondary Qualities, then I don't think there's any reason to maintain that color (sound, smell, taste, etc) is a primary quality. The only reason--so it seems to me--to think that color (etc.) is a primary quality (a property the object has "in and of itself") is to suppose that objects possess colors in just the way we experience them. It is hard to see why you would call any other property color!
Of course, you might say that we should call a property of an object a color because it is a property of the object that causes us to experience it as colored--but that is to say that the property is a secondary quality. And this is just what Locke and many others are claiming. Once you give up the view that color is a primary quality, the only way to continue to maintain that color is a property of objects at all is to treat color as a secondary quality, a quality that objects possess because they cause us to perceive them a certain way.
So much for questions (I), (II), and (III), and hence for question (1). Let us, at long last, briefly touch upon question (2): What is significant about all of this?
This post is already far too long, so I'll try to be brief. The most obvious reason this view about secondary qualities and our ideas of them is important is that, if true, it shows that our experience is, in a fairly straightforward sense, systematically misleading. Experience presents objects and events as having properties that they do not really have. (That said, it is interesting to try to think how experience could be otherwise, particularly if you accept the view that objects are not really colored.)
A somewhat less obvious consequence--though it is one that many early modern philosophers inferred--is that we are never immediately aware of objects outside the mind. The immediate objects of awareness, on this view, are something like mental images ("Ideas"). For if the qualities we are aware of--color, sound, scent, etc.--are not qualities of objects outside the mind, then they must be qualities of objects in the mind. At any rate, this is how many have reasoned.
Now, once one has inferred that the immediate objects of awareness are ideas, it is a short step to Veil of Perception Skepticism about our ability to know anything at all about the external world. For if we are never immediately aware of anything but our ideas, it can be hard to see how we could ever justify any claim about the nature--or existence--of anything other than our ideas.
Ok, enough already! Let's hear what you think. Are the arguments offered above any good? Do you have other arguments for the claims I've discussed? Objections? Counterarguments? Let's hear it!
But now it's time to scrutinize these ideas (if you'll permit the pun!) a bit.
In particular, I want to consider:
(1) Why should believe any of this?
(2) Why is it important or significant?
Let's start with (1). To make progress on this question, I think we'd better distinguish a number of more specific questions that are mashed together in (1). Here are some of the more specific questions we might ask:
(I) Why should we believe that there are any Primary and Secondary qualities, as those qualities have been defined?
(II) Granted the definitions of Primary and Secondary qualities, why should we believe that the examples given of each kind really are instances of those kinds? In particular, why believe that color, sound, scent, etc. are Secondary qualities? Why not suppose they are Primary qualities?
(III) Why should we believe that our Ideas of Secondary qualities do not resemble any quality in objects?
There other questions we might list here, but the above is plenty for this post. Having noted question (I), I'm going to set it aside--I think it loses much of its interest once we've answered (II) and (III). I'm going to begin with question (III), since I think question (II) is easier to answer once we've answered question (III).
So, why should we suppose that our ideas of secondary qualities, such as color, sound, taste, smell and so forth do not resemble any quality in the object? I'm going to focus on the case of color for two reasons: first, it will simplify the discussion; second, it is the most controversial example (and so, if we can make the case with respect to color, we can make it for the other qualities as well).
It is important to remember that your idea of color--or, to be more precise, your idea of a specific instance of a specific color, e.g., your idea of the color of the apple (or whatever) you are seeing right now--is the color as you are currently aware of it; the quality apparently "out there" on the apple. That is your "idea of color". It isn't a very natural usage these days.
Indeed, it isn't a very natural think to think, is it? After all, isn't that color "out there" on the apple just the property red? Well, not according to advocates of the view we are discussing. According to them, the apple as it is in itself, apart from any particular way of experiencing it, isn't colored (in the way we usually think of things as being colored) at all.
One reason is simply that appeals to color, as such, do not appear to play any essential role in explaining anything about how objects interact with other objects. Sure, we appeal to color in everyday explanations--"Why did you buy that shirt?" "I liked the color"--but when we want to get technical, when we want a full explanation, appeals to color drop out of explanations in favor of talk of wavelength distributions, behavior of electrons, and neural activity. (I am not claiming that we can explain everything about color perception, by the way!) If we take Ockham's Razor seriously, we shouldn't believe in properties that play no role in our explanations, then we shouldn't believe that color is a surface property of objects (notice that I am not quite claiming that we shouldn't believe in color at all).
A second argument is this. All object-surface we perceive as colored are, ultimately, composed of atoms. But atoms, of course, are not colored. It is, furthermore, difficult to see how a colored surface could be built up out of ultimately colorless parts. So object surfaces aren't really colored. They simply appear colored because of the way they affect us (via the light they reflect--light which is not itself colored either). Strictly speaking, this argument commits the Fallacy of Composition. Still, insofar as it really is difficult to see how to make a colored surface from colorless parts, this argument creates a challenge for anyone who would maintain that color is a real property of surfaces of objects.
I suspect that most people who doubt that color is a property of objects are persuaded by some version of an argument that we can the "Argument from the Contingency of Color Experience". It goes something like this. The way we experience the color of an object is dependent upon three things: the character of the surface of that object, the character of the light reflected off of it, and the character of our perceptual systems. Change any one of these enough, and the object will appear to have a different color. (Of course, there are problem cases even here: objects that appear black; cases where there is no surface at all--the night and daytime skies; films; and colors of light sources, but let's set those aside for now.) However, it seems to be a contingent fact (a fact that might have been otherwise) that we have the perceptual systems we have, and that the light in our environment has the character it has. Moreover, had we lived in an environment with different ambient light, or had we developed different perceptual systems, we would have different beliefs about the colors of objects--and these beliefs would have seemed perfectly natural to us (as natural as our actual beliefs seem). In light of this, it can seem to quite unlikely that we just happen to (a) have the right sort of perceptual systems and (b) live in a world with just the right sort of ambient light so that the true colors of objects are revealed to us. Why should both (a) and (b) be so, given that things (it seems) could have been otherwise? Our inability to explain this can make our ways of experiencing the colors of objects seem quite contingent--a kind of historical/galactic accident--and this, in turn, can undermine our confidence that we perceive the "true colors" of objects. If you combine this line of reasoning with the arguments offered in the previous two paragraphs, skepticism about the view that objects are colored can begin to seem quite plausible.
Other arguments could be offered for the view that objects are not really colored in the way we ordinarily think they are, but I think I have said enough to convey the overall drift of the arguments.
Now let's recall the point of offering these arguments: it was to answer question (III), above. I think we can see that the arguments offered provide an answer to that question. For if we accept that objects are not colored in the ways we perceive them to be colored, then it follows that our Ideas of Secondary Qualities do not resemble any property in those objects.
Now let's turn to question (II), which is relatively easy to answer at this point. If you accept that no property in objects resembles any of our Ideas of Secondary Qualities, then I don't think there's any reason to maintain that color (sound, smell, taste, etc) is a primary quality. The only reason--so it seems to me--to think that color (etc.) is a primary quality (a property the object has "in and of itself") is to suppose that objects possess colors in just the way we experience them. It is hard to see why you would call any other property color!
Of course, you might say that we should call a property of an object a color because it is a property of the object that causes us to experience it as colored--but that is to say that the property is a secondary quality. And this is just what Locke and many others are claiming. Once you give up the view that color is a primary quality, the only way to continue to maintain that color is a property of objects at all is to treat color as a secondary quality, a quality that objects possess because they cause us to perceive them a certain way.
So much for questions (I), (II), and (III), and hence for question (1). Let us, at long last, briefly touch upon question (2): What is significant about all of this?
This post is already far too long, so I'll try to be brief. The most obvious reason this view about secondary qualities and our ideas of them is important is that, if true, it shows that our experience is, in a fairly straightforward sense, systematically misleading. Experience presents objects and events as having properties that they do not really have. (That said, it is interesting to try to think how experience could be otherwise, particularly if you accept the view that objects are not really colored.)
A somewhat less obvious consequence--though it is one that many early modern philosophers inferred--is that we are never immediately aware of objects outside the mind. The immediate objects of awareness, on this view, are something like mental images ("Ideas"). For if the qualities we are aware of--color, sound, scent, etc.--are not qualities of objects outside the mind, then they must be qualities of objects in the mind. At any rate, this is how many have reasoned.
Now, once one has inferred that the immediate objects of awareness are ideas, it is a short step to Veil of Perception Skepticism about our ability to know anything at all about the external world. For if we are never immediately aware of anything but our ideas, it can be hard to see how we could ever justify any claim about the nature--or existence--of anything other than our ideas.
Ok, enough already! Let's hear what you think. Are the arguments offered above any good? Do you have other arguments for the claims I've discussed? Objections? Counterarguments? Let's hear it!
Monday, February 14, 2011
Hume & Russell & Doors
I am thinking back to HiLo's door picture. How do I know that it is safe to step outside my front door?
I know because every time I step out my door I do so safely.
What if in the middle of the night someone dug a huge pit, so that when I step out my door I fall down and die?
Well, says I, I'll be safe if no one does that.
The more I describe the situation in which I will be safe, the more accurate it becomes.
Example
Opening a door will cause me to step safely outside.
What if it's the door leading to nowhere on a 10-story building?
Opening my house's front door will cause me to step safely outside.
What if there's an ice storm and it's slippery?
Opening my house's front door when there is no ice will cause me to step safely outside.
And so on.
In other words, I know when it's safe when I'm about to open the door and the event closely resembles one in the past when I stepped out safely.
So all I have to do is infinitely describe a scenario in which I was safe that still resembles the current scenario I am in and infinitely open the door and step outside safely. Then, to quote Russell, the general law that that I will be safe when I open my door and step outside shall "approach certainty without limit."
I don't think I've really said anything new here, but it's interesting to think about how we justify day-to-day actions as safe.
What if in the middle of the night someone dug a huge pit, so that when I step out my door I fall down and die?
Well, says I, I'll be safe if no one does that.
The more I describe the situation in which I will be safe, the more accurate it becomes.
Example
Opening a door will cause me to step safely outside.
What if it's the door leading to nowhere on a 10-story building?
Opening my house's front door will cause me to step safely outside.
What if there's an ice storm and it's slippery?
Opening my house's front door when there is no ice will cause me to step safely outside.
And so on.
In other words, I know when it's safe when I'm about to open the door and the event closely resembles one in the past when I stepped out safely.
So all I have to do is infinitely describe a scenario in which I was safe that still resembles the current scenario I am in and infinitely open the door and step outside safely. Then, to quote Russell, the general law that that I will be safe when I open my door and step outside shall "approach certainty without limit."
I don't think I've really said anything new here, but it's interesting to think about how we justify day-to-day actions as safe.
Hume 23.D1
For tomorrow on Hume:
-What is the answer to the problem of induction?
-Why is the problem of induction important to scientific inquiry?
-What is the answer to the problem of induction?
-Why is the problem of induction important to scientific inquiry?
Sunday, February 13, 2011
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!
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!
Wednesday, February 9, 2011
The Primary-Secondary Quality Distinction (Locke)
Our first official topic post!
This post is primarily for discussion of the Primary-Secondary Quality distinction, though of course spin-off discussion is welcome (and bound to occur)!
I'll go ahead and start things off, with a brief description of primary and secondary qualities.
Primary qualities are properties of an object that can be characterized--nearly enough--in mathematical terms, particularly geometrical terms: length, depth, breadth, shape, location, and motion. An object possesses its primary qualities independently of its relations to other objects. In a word, primary qualities are intrinsic qualities.
An object's primary qualities are also objective in roughly Nagel's sense of "objective". That is, objects possess their primary qualities independently of how anyone or anything experiences the object.
Secondary qualities are different. Unlike primary qualities, an object possesses its secondary qualities only insofar as the object is related to other objects. Secondary qualities are thus relational qualities. No object possesses relational properties entirely on its own--other things have to exist. Consider the property of being a brother. Nothing is intrinsically a brother. Being a brother requires that something else exist. So, the property of being a brother is a relational property. Secondary qualities are a bit like the property of being a brother.
Secondary qualities are in fact a special kind of relational quality: they are causal-dispositional qualities. That is, they are qualities an object possesses in virtue of how it affects (or is disposed to affect) other objects. Consider the property of being dangerous. Something is not dangerous in and of itself. (Consider: it does not seem to make sense to suppose that an object could be dangerous if it were the only thing in the entire universe.) Rather, being dangerous is a matter of a thing's being disposed to cause harm to other things (or something like that).
According to Locke (and Galileo and Descartes and many others), color, sound, scent, taste, warmth and cold, and the like are--insofar as they are properties of objects at all--are secondary qualities. They are properties that objects have insofar as they cause (or are disposed to cause) effects in other things.
Actually, we can be yet more specific: these secondary qualities are mind dependent properties. Objects possess color, taste, warmth and cold, in virtue of how they (are disposed to) cause ideas in the minds of perceivers.
For instance, an object is red if and only if it is disposed to cause the idea of red in the minds of certain beings. An object is warm if and only if it causes (or is disposed to cause) the idea of warmth in the minds of certain beings. And so forth.
Now, note that secondary qualities are related to--and dependent upon--an object's primary qualities. For an object will be disposed to cause certain ideas in the minds of perceiving beings only if it possesses the appropriate primary qualities (intrinsic structure). To give a terribly oversimplified example: an object will reflect light differently if its surface "texture" is different. Of course, it will also depend on the nature of the perceiver's mind. But this isn't surprising--secondary qualities are relational properties, after all.
Note that, according to this view of the secondary qualities, objects do not possess them (color, warmth, etc.) in and of themselves. They do possess them--but only in virtue of how they are related (how they are disposed to affect) other objects. Indeed, they are subjective properties in they sense that they depend for their existence upon the existence of subjects of experience (perceiving beings).
So that's the primary-secondary quality distinction. It was widely accepted by early modern philosophers (with some exceptions--Bishop George Berkeley being perhaps the most prominent), and indeed it is widely accepted by scientists today.
But all this is only half the story. Things get a bit more complicated when we bring in the ideas of primary qualities and ideas of secondary qualities. Hm. But I think this is enough for now, don't you? We can talk about the ideas of primary and secondary qualities in another post.
I look forward to your comments on this topic! Does this make sense? What would you like clarified further?
Of course, we've already had one question, and I want to address it here. Olivia asked--and Laura reiterated--the following (good) question: Might it not be the case that the distinction between primary and secondary qualities is a kind of illusion? Perhaps it results from a kind of accident about the way we experience objects. Perhaps we think certain properties (like shape) are primary because we experience them as invariant properties of objects, secondary qualities as variable. But if so, perhaps we simply haven't had the sorts of experiences with objects that would reveal the former properties as variable.
This is a Berkeleyan strategy, insofar as it disputes the distinction between primary and secondary qualities. It isn't Berkeley's way of challenging the distinction though. Perhaps we can get to that later. But let me attempt to respond to this challenge.
The first thing to observe is that the primary-secondary quality distinction is not explained in terms of invariance/variability. The distinction is, rather, drawn in terms of the distinction between intrinsic properties (those an object has independently of anything else) and relational properties (those a thing has that depend on the existence of other objects). These seem to be different distinctions, and if so, the objection doesn't serve to show that there isn't really a distinction between primary and secondary qualities.
Now, the objection might still have force if it turns out that our belief that a property is intrinsic depends on our experiencing it as an invariant property. But I'm not convinced this is true. After all, it is easy to imagine an object that changes its shape every few minutes even if it is the only object in the universe. But then, since there is nothing else, it has a variable, intrinsic property. Moreover, I think we often treat variable properties (like the changing shape of an inflatable balloon) as intrinsic--not dependent on how it affects our minds or indeed on its relations to anything else.
I think there is one other point worth making here: and this is that I'm not sure it makes sense to suppose that all of an object's properties could be relational (secondary). Relational properties, it seems, have to be "grounded" in non-relational (intrinsic, primary) properties. For now, I'm going to leave this claim unargued for. It sounds like a perfect topic for further discussion after all!
Tuesday, February 8, 2011
What do you want to think about?
Let me know what you want to discuss (by leaving a comment below), and I'll create a new post where we can think it through!
Raise topics from class for further discussion.
Ask questions that occurred to you in class that we didn't get to discuss.
Respond to comments other students made in class.
Or just think out loud! Whatever. Let's just continue the discussion!
Subscribe to:
Posts (Atom)