Thursday, November 16, 2006

A Post On Postmodalism or It Feels Good To Could Have Been A Zebra

The other day, my discussion with Oscar about vague essential properties (see the Comments section to his "RG Modality"-post turned into a nice beer-fuelled evening of talk, laughter and goodnatured name-calling. The topic soon expanded to the venerable question whether there are essential properties at all, with a bunch of people split quite nicely over the issue. Oscar was joined by Manolo M. on the "of course there are" front, while I was joined by Sanna on the side that was soon called "the Postmodernists", which I still find very amusing. Jose C., Pepe and Guido took up various positions in the middle, and off we were.

I won't try to record the whole thing, but here's a taste of the strange arguments that were produced (that's the nice thing about writing a post, by the time the others get to quote the strange arguments you yourself came up with after your third beer, they're already in the relatively obscure Comments section...):

In the case of the discussion whether Pluto and Sedna (or how that thing was called) were planets, what was at stake was to find a definition that captures the essential property "to be a planet". That is to say, either it was (at that time) objectively false to call Pluto a planet five years ago, or it is objectively false to deny that Pluto is a planet today.
If you find that bizarre, it might be because you're a postmodernist as well, or, as Oscar later suggested, a postmodalist.


Oscar Cabaco said...

I'm sorry, but Pepe actually believes in essential properties. He just lies because he knows that that really annoys me ;-)

To be a planet is NOT an essential property: if you take Mars off of its orbit so it just stops moving around the sun it will stop being a planet. But this doesn't mean that 'planet' is not a natural kind.

Though I have strong pro-modalist prejudices, and I think this is not a serious discussion, I should mention that last year we already discussed a similar topic in the Natural Kind Essentialism Reading Group. In this reading group we read articles that challenged the Kripke/Putnam view regarding natural kinds. For instance, we began reading Donnellan's Kripke and Putnam on Natural Kind Terms, in which (if I remember well) he argued that the identification of gold with the element with the atomic number 79 was partially conventional and arbitrary (it was in part an historical contingency.) I also remember Dupre's Natural Kinds and Biological Taxa, in which he defended that plenty of alleged natural kind terms of the ordinary language don't correspond to natural kinds identified by science. And we also read papers by Laporte, Henry Jackman, I. Hacking, Mark Wilson, Segal, J. Brown, etc.

But surely my memory isn't especially good. It would be great if someone who also attended this reading group (and who has some time to spare writing for this blog) can summarize the main points of the discussion, or his/her opinion on this matters. Any volunteer? (Maybe Pepe, who also attended the reading group, should say something about this n order to redeem his countless sins :-)

(Needless to say, of course, that I was on the side of those defending the classical inherited view on natural kinds.)

If you let me to choose I prefer to be another animal rather than a zebra in other possible worlds...

Sanna Hirvonen said...

Hey essentialists and postmodernists!

On Oscar's point (2):
If you take Mars, a perfectly decent piece of astronomical ontology, and try to define it, you will immediately come up with the term 'planet' in describing it. (You would probably start your presentation saying something like: "Mars, also known as the Red Planet bla bla".) What defines Mars is basically its being a planet and its location. So isn't "being planet" the essential property of Mars? (Pretending for a while there were any essential properties :)) If you did take Mars off of its orbit, I would say that Mars would stop being a planet and therefore it would stop being Mars. To persuade your intuitions I will give an example: an encyclopedia would say of Mars something like "The former fourth planet from the sun. Left its orbit in 2007. The rock formerly known as Mars is now floating towards Andromeda." (Sorry for the astronomical absurdities!) So I think the things in our solar systems called Mercury, Venus etc. have planethood as their essential properties.
I don't know anything about essential properties since really I don't think they exist, but if they did, why wouldn't 'being a planet' be such?


Sanna Hirvonen said...

Just to clear out some points: what I just said might seem like saying that Pluto is not Pluto anymore since it is not a planet after all; if Mars is essentially a planet and it stops being Mars if it loses its planethood, then why doesn't it hold in the case of Pluto? Because Pluto was never an "exemplary planet" so we were simply mistaken in saying that it was a planet, not mistaken in calling it Pluto. :) The point of this is that there has to be some planets that define the "essential property" of being a planet, and let's hope for the sake of my former example that Mars is such. It simply could not happen that all planets turned out to be something else than planets, that's a conceptual impossibility!
In other words, Mars defines planethood and planethood defines Mars (and the same goes for some other typical planets), but Pluto was called a planet only by a mistaken argument by analogy...

Dan López de Sa said...

As I understand this, both Oscar and Sanna agree that it is not an essential property of Mars that it is a planet (de re), but Sanna points out that this is compatible with Mars being essentially a planet (de dicto). Am I understanding this right?

Oscar Cabaco said...

First, my answer to Dan. In certain sense, we agree in that Mars is not essentially a planet, but for completely different reasons. The difference between us is that Sanna would claim that, if Mars has (so to speak) de re essential properties, then to be a planet is one of them. In contrast I think that Mars has essential properties in the standard sense but to be a planet is not one of them.

And secondly, I'll try to spell out my reasons to hold that Mars is not a planet.

Which is the difference between a planet and a mere satellite? Just one: the way they move. If Mars orbits another bigger celestial body, it will become a satellite and will stop being a planet.

Maybe you'll admit that Mars is a planet because its orbit but you would still want to hold that this is an essential property of Mars. But then, do you know any other example of object that has as an essential property the way it moves?

I must confess that I don't share Sanna's intuitions with respect the examples she gives. For example I deny that “If you did take Mars off of its orbit, I would say that Mars would stop being a planet and therefore it would stop being Mars.”

But in order to defend my intuitions I'll try to give another description of her example. Let's suppose that a goddess see the solar system and decides to move Mars out of it. Did she destroy any object? According to Sanna's intuitions indeed she destroyed Mars, but not according to my intuitions, because the essential properties of Mars are just those of a big dusty ball of rock.

But I guess that we can only settle this with a poll. At least, after the poll we will know which one is the standard concept of planet. So don't hesitate and give you opinion!

Dan López de Sa said...

Oscar's recent 1 only supports the de re claim, does not go against the de dicto one, which might accout for 2.

As to 3, I found the "destroying" intuitions potentially misleading: do you destroy the Golden Bachelor when you marry him? Well: in virtue of marrying, he is no longer the Golden Bachelor, the Golden Bachelor no longer exists!

I took Sanna to be making a similar point wrt Mars: if the object that actually is Mars cease to fall under 'is a planet,' it would thereby cease to be Mars.

(One consequence would be, of course, if one grants the de re claim, that Mars is only contingently Mars. Which is not to say that it is not neceesarily self-indetical!)