What scientists know 
I put a draft of my paper, What scientists know is not a function of what scientists know, on my website and on the PhilSci archive a couple of weeks ago. I'll be presenting it at the PSA in November.

ABSTRACT: There are two senses of 'what scientists know': An individual sense in which scientists report their own opinions, and a collective sense in which one reports the state of the discipline. The latter is what is of interest for the purpose of policy and planning. Yet an expert, although she can report the former directly (her opinion on some question), can only report her considered opinion of the latter (the community opinion on the question). Formal judgement aggregation functions offer more rigorous frameworks for assessing the community opinion. They take the individual judgements of experts as inputs and yield a collective judgement as an output. This paper argues that scientific opinion is not effectively captured by a function of this kind. In order to yield consistent results, the function must take into account the inferential relationships between different judgements. Yet the inferential relationships are themselves matters to be judged by experts involving risks which must be weighed, and the significance of the risk depends on value judgements.

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What I'm reading now 
In What to believe now [Amazon/GoodReads], David Coady sets out to do applied epistemology. Most of the book is about expertise and democracy,* which is fine. With the caveat that I haven't read it all, I'll lament that fact that most of the book seems to be Coady summarizing and critiquing Alvin Goldman's work on these topics. Missing, for example, is any discussion of Harry Collins' work on expertise.

Wikipedia is discussed for three pages in the conclusion, and I'll focus on that because he quotes me. Coady writes:
Most contributors to Wikipedia, unlike most rumor-mongers, see themselves as engaged in a single collective enterprise. This enterprise is governed by rules, and Wikipedia has a hierarchy that seeks to enforce those rules. So, when P.D. Magnus characterizes the claims made in Wikipedia as "more like 'claims made in New York' than 'claims made in the New York Times" he is mistaken. ... Wikipedia is a reasonably reliable source for a reasonably wide range of subjects because of the contingent fact that it has a reasonably good culture at the moment.

Perhaps the rhetorical flourish in the passage he cites overstates my point, because claims in Wikipedia fall under one institutional umbrella in a way that claims made in New York do not. But my point is that there is sufficient variation in the quality and reliability of Wikipedia articles that it is wrong to treat them all together. Even though it is 'reasonably reliable' across a 'reasonably wide range', it is better to pay attention to the kind of article that you are consulting. Wikipedia is large enough that it is better to think of it as multiple overlapping communities, rather than as a single monolithic culture.

* EDIT: As Coady points out in the comments, there are also chapters on rumours, conspiracy theories, and blogging.

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Counting on universals 
In A Quinean Critique of Ostrich Nominalism (March 2012) Bryan Pickel and Nicholas Mantegani argue that so-called ostrich nominalism is less parsimonious than realism about universals.

Here's the background: The realist asks what can explain the fact that (for example) all blue things have something in common. The explanation, the realist says, is that the blue things all participate or instantiate a further thing: blueness, a universal. The ostrich nominalist denies that there is any explanation required; at least some things are brutely similar.

It is natural to think that the realist gets more explanatory power (giving an ontological basis to similarity) at the cost of complexity (adding universals to the ontology). That is to say that the realist account is less parsimonious. Pickel and Mantegani argue the opposite.

They develop their argument using this schematic case: "Box World: There is a blue sphere. There is a green cube. There is an orange sphere. There is a blue cone."

They then count up how many basic sorts are in the nominalist and realist ontologies. For the nominalist, they count six:

N1: Exists x Blue (x)
N2: Exists x Orange (x)
N3: Exists x Green (x)
N4: Exists x Sphere (x)
N5: Exists x Cube (x)
N6: Exists x Cone (x)

The realist does not need separate elements for Blue, Orange, and all the rest. Rather, the realist just has the two-place instantiation relation. 'There is a blue thing' is regimented for the nominalist as Exists x Blue (x) but for the realist as Exists x IS(x,blue). Counting basic sorts for the realist, they count four:

R1: Exists x Universal(x)
R2: Exists x Particular(x)
R3: Exists x Exists y IS(x,y)
R4: Exists x Exists y IS(y,x)*

One might object to this accounting on the grounds that the realist ontology simply has more things than the nominalist ontology has got. The former has four particulars plus six universals, whereas the latter just has four individuals. They spend some time addressing this objection and distinguish between quantitative simplicity (having fewer things) and qualitative simplicity (having fewer sorts of things). The objection mistakenly attempts to apply Occam's razor along quantitative lines, where the principle ought to cut along qualitative lines.

I am sympathetic to their reply, so lets pass over that objection.

The greater objection is that they have not fessed up to all of the complexity in the realist account. The realist is not merely adding the four sorts enumerated in R1-R4. In order to regiment the original description of Box World, the realist must say things like Exists x (IS(x,blue) & IS(x,spherical)). Rather than merely adding some number of universals, this requires that the universals be named. Depending on our choice of logic, the name blue might be a constant or an implicit predicate. In either case, it is a further bit of basic machinery.

There are six named universals, so the realist requires six further basic elements. Contra Pickel and Mantegani, and pro the usual intuition, the realist has a less qualitatively simple account than the nominalist.

* Perhaps their list could be winnowed down. R3 and R4 might be merged together, on the grounds that instantiation is brutely relational. Then R1 and R2 might be defined in terms of instantiation; e.g., to be a Particular is just to be something that is in the first place of the instantiation relation. If my argument at the end is right, then this cutting and shaving won't be enough.

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Gaiman on simulated wisdom 
In a commencement address at University of the Arts in Philadelphia, Neil Gaiman offers the following advice:
Be wise, because the world needs more wisdom. And if you can not be wise, pretend to be someone who is wise and then just behave like they would.

I first thought that this would be impossible, because accurately simulated wisdom would just be wisdom. Yet perhaps genuinely being wise requires not only right action but also understanding, and so one might do what a wise person would do but without the wise person's understanding of entirely why. So the advice is possible.

Whether it is good advice depends on whether it is any easier to simulate wisdom than to actually be wise. Imagine predicting what a wise person will do, holding fixed the assumption that they are wise. In some vexed cases or thought experiments, the prediction might require actually being wise yourself. But you might be able to predict fairly well for quotidian decisions without actually having wisdom. In such cases, Gaiman's advice seems sound.

There is a further question of moral philosophy whether following this advice would be right and proper. If goodness and wisdom are related, do they require the right interior understanding or just the right action? I don't know, but I am inclined to think that right action with wrong thinking is prima facie better than wrong action with wrong thinking.

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Package deals 
As I argue in several papers about realism, philosophers should give up their obsession with monolithic questions of realism and antirealism. So I try to emphasize other things when I teach philosophy of science. Some of these other things are causation, explanation, laws of nature, and attitude toward unification.

Positions on these issues arrange themselves into roughly three categories. Interestingly, although each has a different metaphysical picture, they are neutral on questions of realism or antirealism about unobservable entities. For example, adopting the Humean outlook of the epistemic package is compatible with affirming or denying that facts about electrons are on the list of Hume facts about the world.

The EPISTEMIC package

Exemplary adherents include Hempel, Lewis, et al.

Metaphysics: Only actual objects and events are real.
(Alternately: Only concreta exist.)

Causes are regularities.

Laws are the fundamental regularities that appear in the best system.

Probabilities are subjective credence.

Explanation is a matter of nomic expectability. The DN account (or some relative of it) using elements of the best unified system.

Unification of science is constitutive.

The MODAL package

Exemplary adherent: Armstrong

Metaphysics: Actual objects and events are real, but so are modal facts.
(Alternately: Concreta exist, but so do universals.)

Causes are relations between properties.

Laws are the fundamental necessities, relations between universals.

Probabilities could be subjective or objective (but I think that there's some pull toward subjective accounts).

Explanation is a matter of nomic expectability. The DN account (or some relative of it) using genuinely necessary laws.

Unification of science is contingent.

The ONTIC package

Exemplary adherent: Cartwright

Metaphysics: Actual objects and events are real, but so are causal capacities.

Causes are exercises of capacities, the powers of things.

Laws are a patchwork, summaries of what capacities can do in particular arrangements.

Probabilities are objective, determined by the capacities of things.

Explanation is a matter of identifying causes.

Unification of science is doomed.

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