Sunday, May 25, 2008

21st Century sophistry: The use of the opinions of social scientists as empirical fact.

There has been a tendency in philosophy to take some piece of research from social psychology to prove beyond doubt some point in favour of the philosopher’s favourite theory. Through a kind of slight of hand, the general maxim that one must not doubt hard empirical fact just because it conflicts with cherished beliefs, seems to forbid a questioning of the often highly subjective and biased interpretations of the evidence by the scientists who conducted the study. Whereas often, even a cursory examination of the original case study shows the results to be open to a number of equally valid interpretations. There is no general argument against this unhealthy philosophical strategy. It is incumbent on us all to remain vigilant against this pervasive bit of twenty first century sophistry.

In “Knowledge and its Place in Nature”, Kornblith develops an argument against the epistemic good of reflection by referring to some social psychology data about the “position effect”. The position effect is the tendency to select things to the right when asked to choose the most preferable out of a selection of similar consumer goods. Kornblith quoted an account of a study by Nisbett and Wilson.

“Passers-by in a shopping mall were invited to examine an array of consumer goods (four nightgowns in one study, four identical nylon panty-hose in another) and to rate their quality. There was a pronounced position effect on their evaluations, such that the right-most garments were heavily preferred to the left-most garments. When questioned about the effect of the garments’ position on their choices, virtually all subjects denied such an influence (usually with a tone of annoyance or of concern for the experimenter’s sanity)”

First let me point out that really we should ignore the parenthesis at the end. It must be annoying enough to be asked to rate the relative quality of identical panty hose. To then be asked whether you chose on a different basis from the one you were asked to choose upon just is annoying, and a peeved tone should be expected. The perceived tone of annoyance and concern for the experimenters sanity cannot be counted as data. It is Nisbett and Wilson’s interpretation of the subjects unspoken conversational intentions, which is already influenced by their hypothesis.

Kornblith explains the position effect by claiming that the subjects reconstruct the reasons for their choice after the event on the assumption that they made their choices on a rational basis. Kornblith asks the rhetorical question:

“How else could we possibly explain that those who are influenced by the position effect in judging the quality of consumer goods explain the source of their judgements as lying in objective features of the goods whose quality they judge?”

What would be the effect in the dialectic of giving a good answer to this question? Would it show that Kornblith’s theory of knowledge was false? Far from it. All it would show is that his use of empirical data is irrelevant to his argument. It merely has a rhetorical effect of luring the reader into thinking his arguments are supported somehow by hard psychological fact (if there is such a thing).
Here is how I answer Kornblith’s rhetorical question: the source of their judgements do actually lie in objective features of the goods whose quality they judge. The reason that the subjects deny the influence of the position in their decision is because the position didn’t influence their decision. This explanation has the wonderful bonus of fitting in with the first person reports of the people under investigation. Whereas Nisbett and Wilson’s bizarre hypothesis requires that they ignore this strong disconfirmatory evidence, claiming instead that the subjects are lying, or otherwise falsely reporting their own reasons and preferences.
But hang on, didn’t they prove empirically that the position influenced the subject’s preferences? No, all their results showed was that people tended to choose the far right item more often that the far left item. This is a lesser and distinct proposition from that the position of the item was a reason for their preference. This latter exciting hypothesis requires further argument. But the skewed preferences still need explaining. So here goes: people in general read from left to right and will survey a range of choices left to right. Nisbett and Wilson’s passers by had to make a single best choice out of 4 items. Let’s call them 1, 2, 3 and 4. A good cognitively efficient and time efficient strategy is to compare each one to its immediate predecessor. If you are by and large indifferent then there is no need to track back when you get to the end of your sequence. So you just choose the last one. This is making a selection as required over an issue that is of no importance when there really is no clear winner. It is not making a decision on the basis of position, but it does have the consequence that people will tend to choose 4 much more often than 1.
Perhaps this does not seem very convincing, so here is another problem. Which man do you settle down with and have a family? If you choose too early then you may settle for someone who is not as ideal as a later choice. If you wait too long, you may let the real love of your life go. It shouldn’t surprise a naturalist if human beings were very adept at solving this particular problem, since it is *the* problem of sex selection. With a little idealisation the problem can be solved mathematically. What you do is to estimate the number of eligible men you are likely to meet and think of them as a sequence. So let us suppose you are likely to meet 30 men in a life time if you keep breaking up after a year. What strategy will help you find the best man to marry? Well, we just need two values: best yet and over all ranking. Man 1, your first love, is clearly bound to be best yet, however much of an oaf he is. Man 2 has a 50% chance of being best yet, Man 3 has 33.3% of being best yet, etc. Now we can calculate the probability of any best yet being the best over all. The best yet Man 1 is 1 in 30, if Man 2 is best yet then he has 1/15 chance of being the best over all, etc. Given this model, it can be worked out that you should settle for any best yet after Man 11. This model assumes that you can’t go back to a previous relationship. In real life its obviously much more messy and complicated, but for a given socio economic climate we mind find that women tend to settle down with the next best yet man they meet when they reach a particular age, say, 28. If this were the case, would it be evidence that people’s selection of their beloved is based on or influenced by the age at which they met? Well, kind of, but you can expect some pretty hostile and annoyed looks if you were to tell somebody that the reason they married their husband was not because of his great beauty, wit, kindness or anything like that, but just because she was 28 when they met. This inference is absurd, and there would be some doubt as to the rationality of someone who thought that they had somehow established this as fact.
In selecting nylon pantyhose for the amusement of an on looking psychologist, the stakes are obviously not that high. In a tie situation the current choice may as well count as the best yet since it has the advantage of being fresher in your mind and nearer to hand. But because of the fact that in the panty hose experiment, you can go back, there is no disincentive to going to the end of the sequence. The result being that we should expect people with no pressing interest in the matter to tend to select the item on the furthest to the right if the qualities that inform the judgement of whether an item is the best yet are fairly uniform. (When I made the final decision, the last one I looked at came to mind most strongly) This is perfectly consistent with a denial that the position of the pantyhose influenced the decision. (I just love things that are furthest to the right).
How would I introspectively report how I had come to my decision if I used this strategy on four identical pantyhose?

I looked at the first one and it seemed ok, I looked at the second one and it seemed no different, maybe slightly better if anything, I looked at the third and again, no real difference, but perhaps slightly better, then I looked at the fourth, and really, I had no basis to prefer any but the last one did seem slightly better that the previous one. So I chose number 4.

This is what I would predict would be most peoples reflective assessment of their decision process. The seeming progressive improvement would be just on account of preferring the present choice to a previous one in tie situations to allow for the slight disutility of going back for another look. How often have you heard people saying that the book they are reading is the best book they have ever read? Americans in my experience have a tendency to be emphatic, and anyone with half a brain will not change their preferences on what looks like the prompting of a sales person. So a bit of “No way, number four is by way the best pair of pantyhose I have ever seen in my life,” is to be expected. But this verbal emphasis may be reduced somewhat if you offered them number 1, 2 or 3 for free, or 4 at the recommended retail price. The preferences that were so strong in the subjunctive tense would soon evaporate. That’s my prediction, test it if you like. I have no intention on wasting people’s time getting them to give a preference ordering over identical pantyhose. Whatever the results, they cannot possibly allow me to accept the conclusion that a good meditative reflection on difficult philosophical issues is not the best epistemic practice we have.
Jonny Blamey

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Friday, June 29, 2007

"Probabilistic Semantics for Epistemic Modals" Moritz Schulz, New College oxford

The Thesis

It is prima facie plausible that “might” and “must” express a certain kind of
epistemic modality. We shall assume that “might” expresses some kind of epistemic possibility and that “must” can be used to express a corresponding kind
of epistemic necessity. Evidence for the view that “might” and “must” provide
an interdefinable pair of modals can be gained from examples like the following:

(1) They might be away.
(2) No, they must be at home.

It seems to be intuitively plausible that (2) is the negation of (1). In what
follows, we shall thus assume that “might” and “must” are interdefinable (in
their epistemic usages). In our informal discussion, we shall be mainly concerned
with “might” because it seems to be less ambiguous than “must”. Besides, we
shall only deal with indicative or present tense usages of “might”.
A good starting point for our investigation into the semantics of “might” is
the following observation:
(Basic Observation)
We are prepared to assert “It might be that X” iff our credence in X
is positive, i.e. iff C(X) > 0.
If one is not sure that they are away, one is in a position to say “They might
be at home”. And if one is sure that they are away, one should reject that they
might be at home. Moreover, the basic observation seems to provide a good
explanation why it would be an odd thing to say
(3) They might be at home, but I am certain that they are away.
Now, assuming that the basic observation gets the assertability conditions of
“might”-statements about right, we can go on and ask what our credence in a
“might”-statement should be. Since assertability goes by high credence, it follows
from the basic observation that our credence in a “might”-statement should be
high iff our credence in the embedded statement is non-zero. Actually, I would
like to argue for a more definite thesis:
(MIGHT)
Our credence in “It might be that X” should be 1 iff our credence
in X is positive and it should be 0 iff our credence in X is 0. Thus
C(Might X) = 1 iff C(X) > 0 and C(Might X) = 0 iff C(X) = 0 for
C being any reasonable credence function.

My main reason for proposing MIGHT stems from the observation that beliefs
in “might”-statements do not come in degrees. Rather, it seems to be an all or-
nothing matter. For instance, we usually do not qualify a “might”-statement
with a phrase such as “probably” which can be used to compare the likelihood
of statements. It is rather odd to say
(?) Probably they might be at home.
Also, we do not say that one “might”-statement is more likely than another:
(?) It is more likely that they might be at home than it is that they might be
away.
All this is evidence for allowing a “might”-statement to receive only two values.
In addition, it is hard to see what kind of further evidence (over and above nonzero
credence) would be needed in order to be certain about a “might”-statement.
It seems to be enough to give the embedded statement some (subjective) chance
of being true. So, it seems that one can make a good case for MIGHT.
Given our assumption about the interdefinability of “might” and “must”, our
thesis has a natural counterpart.
(MUST)
Our credence in “It must be that X” should be 1 iff our credence
in X is 1 and it should be zero otherwise. Thus C(Must X) = 1 iff
C(X) = 1 and C (Must X) = 0 iff C(X) < 1 for C being any reasonable
credence function.

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Monday, March 05, 2007

What is Space, Stephen Tiley

The Reality of Space


Two questions immediately arise:

1) what is space? [metaphysical question]

2) how can we know space? [epistemological question].

Needless to say, both questions are intricately connected: in order to ask what space is we must ask how, if at all, we can know acquire knowledge of it.

The two main historical positions concerning the nature of space are absolutism [or substantivalism] and relationalism.

Absolutism, most prominently expressed by Newton , argues that space has an existence over and above the objects contained within it.

Relationalism, most prominently expressed by Leibniz, argues that space has no existence over and above the relations between objects contained within it.

Both offered intricate arguments to support their respective positions.

According to Newton , as space is ontologically prior to the objects contained within it, viz., space can exist even when there are no objects contained within it, his view entails that objects in space can have absolute positions and velocities.

For Leibniz, on the other hand, space exists only as a relation between objects, and therefore has no existence apart from the existence of those objects; motion exists only as a relation between those objects.

Leibniz believes that such notions as absolute position and velocity, as espoused by Newton ’s absolutism, are meaningless and lead to contradictions.

The two arguments he offers us rely on his principle of sufficient reason and the identity of indiscernibles.

Leibniz thought-experiment:
He asks us to imagine two universes situated in absolute space. The only difference between them is that the second is placed five feet to the left of the first, a possibility available if such a thing as absolute space exists. Such a situation, however, is not possible according to Leibniz, for if it were:
a) where a universe was positioned in absolute space would have no sufficient reason, as it might very well have been anywhere else, hence contradicting the principle of sufficient reason, and
b) there could exist two distinct universes that were in all ways indiscernible, hence contradicting the Identity of Indiscernibles.


In defence against Leibniz, Newton offered us his famous ‘Bucket’ thought-experiment.

Newton’s Bucket:


The rotating bucket argument attempts to show that true rotational motion cannot be defined as the relative rotation of the body with respect to the immediately surrounding bodies. It is one of five arguments from the "properties, causes, and effects" of true motion and rest that support his contention that, in general, true motion and rest cannot be defined as special instances of motion or rest relative to other bodies, but instead can be defined only by reference to absolute space.

Water in a bucket, hung from a rope and set to spin, will start with a flat surface. As the water begins to spin in the bucket, the surface of the water will become concave. If the bucket is stopped, the water will continue to spin, and while the spin continues the surface will remain concave. The concave surface is apparently not the result of the interaction of the bucket and the water, since the water is flat when the bucket first starts to spin, becomes concave as the water starts to spin, and remains concave as the bucket stops.

This argument attempted to demonstrate the necessity of the existence of absolute space to account for phenomena like rotation and acceleration that cannot be accounted for on a purely relationalist account. Clarke argues that since the curvature of the water occurs in the rotating bucket as well as in the stationary bucket containing spinning water, it can only be explained by stating that the water is rotating in relation to some third thing, namely absolute space.

http://www.bun.kyoto-u.ac.jp/phisci/Newsletters/bucket.jpg

According to Newton , absolute space has the following properties:

1) Space has an ontologically prior existence to the objects contained within it.
2) Space can affect the objects/matter contained within it, but these objects cannot affect/influence space itself.

On a first reading absolute space seems to be endowed with a rather bizarre ontological status: it can exert an influence on objects contained in it but cannot itself be affected. It is immutable, eternal and unchanging.

Furthermore, if we cannot exert and influence of space itself, how can we possibly acquire knowledge of its existence?

As all we can really interact with are the objects contained within space, surely it follows that only these objects can be said to exist….?

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