TeX doodle recognition 
Via TAR, I just discovered the group blog PhilTeX which is about technology for philosophers. And via PhilTex, I discovered Detexify. This latter item is a very clever web page for finding LaTeX symbol commands. It allows you to doodle in a symbol. Then it suggests various LaTeX commands for producing symbols like the one that you drew. Nifty!

[ add comment ] ( 3786 views )   |  [ 0 trackbacks ]   |  permalink
Should we phone ET? 
Stephen Hawking has been a great science popularizer. I first encountered his work when I was in junior high school. Before that, when people had asked what I wanted to be when I grew up, my standard answer had been cartoonist. After Hawking, my standard answer was astrophysicist. I went on to be a physics major as an undergraduate, which combined with my interest in philosophy to become a specialty in philosophy of science.

I am late to the blogging about this, but Hawking recently headlined a documentary series which, among other things, discussed the prospects of extraterrestrial life. The London Times story is typical; other news sites offer distinct but similar coverage.

There is likely to be alien life, Hawking reasons, because the universe is big. Crudely, the idea is that one should expect that any outcome which could does occur somewhere in a place that big. Extraterrestrial life is such an outcome, so we should expect it. This is pretty standard. It's the same as the reasoning in the Drake Equation, although Drake ornamented the argument with numerical probabilities so as to give it the illusion of rigor.

Yet the headlines were not that Hawking believes in aliens. Rather, it's that Hawking recommends against reaching out to alien civilizations. Aliens, he suggests, are likely to be a dangerous. The Times quotes him:
We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach.

Perhaps aliens would be jerks like us.

The prediction that they would be is certainly not a scientific one, and it is not within the purview of physics. So he's really out of his depth in speculating as to whether advances species are more likely to be saints or sinners.

Yet physics does have something to say about is the feasibility of traveling from world to world and pirating planets the way Somalians pirate a freighter. Physics is pretty down on the possibility. Hawking invokes artificial wormholes or whatever, but we're really in the science fiction turf of technobabble.

Kurt Vonnegut, in a little story called 'The Big Space Fuck', says this:
One of the most depressing things about the space program... was that it had demonstrated that fecundity was one hell of a long way off, if anywhere. Dumb people... and even fairly smart people... had been encouraged to believe that there was hospitality out there, and that Earth was just a piece of shit to use as a launching platform. Now Earth really was a piece of shit, and it was beginning to dawn on even dumb people that it might be the only inhabitable planet human beings would ever find.

The thing that Vonnegut has people realizing is the gist of what physics actually tells us. Hawking is saying what people had been encouraged to believe, only striking 'hospitality' and writing in 'malevolence'. Science fiction authors may introduce chronosynclastic infundibulae, but travel between here and any point where there might be extraterrestrial life is going to be too slow and too costly to make sense for even the most nomadic of space jerks.

I concede that my reaction is based on the marketing for Hawking's TV specials. There is, no doubt, some good science in them. Yet I find the whole thing a bit disappointing.

[ 1 comment ] ( 7676 views )   |  [ 0 trackbacks ]   |  permalink
Straight shooting about red herrings 
My paper about the new induction has now appeared on the BJPS website.

[ add comment ] ( 3125 views )   |  [ 0 trackbacks ]   |  permalink
Deconstructive empiricism 
I've been thinking about Bas van Fraassen's epistemology. Here are some distinct points: a clarification, an objection, and a question

The clarification

The usual story goes like this: Anti-realism as a semantic doctrine was seen to be a dead letter, but van Fraassen's The Scientific Image resuscitated it as an epistemic doctrine. In the decades since, a thriving literature in scientific realism has developed. Realists disagree among themselves about exactly why, but they generally agree that we ought to believe our best scientific theories - including its unobservable posits.

This becoming the crux of the issue is ironic, because this form of 'scientific realism' is not opposed to van Fraasen's anti-realist constructive empiricism.

First, because van Fraassen thinks that this way of posing the problem is confused. He thinks that rationality never obligates us to believe anything. Rather, it gives us permission. Given such an account of rationality, its simply misleading to ask whether we ought to believe any specific thing. Moreover, he admits that it is permissible to believe in the unobservable posits of our best theories.

Second, because van Fraassen doesn't see the disagreement as one about epistemic attitudes at all. Instead, it's about the proper aim of science. He puts the point this way:
Scientific realism and constructive empiricism are. as I understand them, not epistemologies but views of what science is. Both views characterize science as an activity with an aim - a point, a criterion of success - and construe (unqualified) acceptance of science as involving the belief that science meets that criterion. According to scientific realism the aim is truth (literally true theories about what things are like). Constructive empiricism sees the aim as not truth but empirical adequacy.*
And that's the catch.

The objection

I don't think science as an activity has a singular point. I haven't argued this at length, but I intimate it in my dcog paper.

Of course specific scientific projects can have identifiable purposes. A particular drug trial may be to determine whether the drug is safe and efficacious, for example.

And of course specific scientists may be involved in science for identifiable reasons. This may be to discover truths, to make true predictions, to make the world a better place, or just to impress their parents.

Scientific realism and constructive empiricism both need more. They need there to be a purpose to science altogether - SCIENCE write large. Even supposing that there is such a purpose, it is not something that can be divined by a priori rumination. As van Fraassen admits, our account of what science is about must accommodate the actual history of science. It is a partly empirical enquiry responsible to evidence.

In this enquiry, what are the phenomena? Conservatively, we might answer that the phenomena are historical documents and physical evidence. More liberally, we might say that phenomena are the actual historical activities of scientists.** Yet under no account is the aim or purpose of the activity itself among the data. The aim of the activity is a posit, introduced as part of a philosophical-historical theory. Moreover, it is an unobservable posit.

Therefore, an agnostic (who declines to believe in the unobservable posits of even the most successful theories) must decline to believe in the aim of science. This follows regardless of what the aim of science is posited to be, so an agnostic must decline to be a constructive empiricist.

This would be a problem for van Fraassen, who thinks that agnosticism is a natural position for constructive empiricists. I see two possible replies.

First, he might stick to his agnostic guns. Refusing to believe in constructive empiricism, he still might accept it. That is, he could treat constructive empiricism as involving not a true theory about science but instead an empirically adequate one. This involves some mental gymnastics, but being an agnostic already involves mental gymnastics. This meta move is only a small additional flourish.

Second, he might deny that the aim of science is a theoretical posit. Perhaps history is not a science. Perhaps discovering what what science is is not history. I don't see this line as terribly promising.***

The question

Van Fraassen has argued that we need a richer epistemology, one which allows for more than just binary beliefs or probabilistic degrees of belief. Moreover, he resists formal models of belief as direct representations of entities in the mind or brain. Yet he does seem to genuinely believe in states of opinion, "real epistemic attitudes, pointed to by traditional epistemology, which cannot be accommodated in the probabilist models we have developed so far."*

As Sellars and Churchland convincingly argue, though, epistemic attitudes like this are not among the immediate phenomena of the world. We posit them as part of a (folk) psychological theory. An agnostic about scientific and folk scientific theories ought not to believe in beliefs.

Does van Fraassen acknowledge this anywhere? or is his psychological musing a personal matter rather than an announcement ex cathedra qua constructive empiricist?

* Analysis 58.3, July 1998
** Even van Fraassen would allow the more liberal construal, since he thinks that past objects count among the observables.
*** Admittedly, I see science as basically synonymous with responsible enquiry. For someone with a narrower conception of science, perhaps this line of response could go further.

Note: I cross-posted at It is only a theory, and there are lively replies there as well.

[ 3 comments ] ( 7119 views )   |  [ 0 trackbacks ]   |  permalink
x 1.28 
Last week I released a new version of forall x: 1.28. It corrects several typographical errors, some of which make a substantive logical difference.

The blurb description on the back page still says 'assistant professor', although that is only accurate for the moment. My tenure is waiting only on the signature of the university president, which I'm told is a formality. I have even signed the relevant employment paperwork for the change to associate.

[ 2 comments ] ( 5590 views )   |  [ 0 trackbacks ]   |  permalink

<<First <Back | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | Next> Last>>