Monday, May 14, 2018

Is Pluto A Planet?

   Seems like a borderline case of a planet, to me. Perhaps more planet than not. But there's really nothing very interesting about it, and not a lot more to say about it. (IMO) The natural world is full of continuities and borderline cases. Per Peirce, that's just the way real classes tend to be. Contra nominalists, social constructivists, etc., blurry boundaries aren't a sign of made-up groupings. Rather, sharp boundaries are more likely to be a sign of something made up. There's a real difference between a juvenile human and a mature human, but the transition from the former to the latter is gradual. But for legal purposes, it happens in clear, sharp stages: once at midnight on your 18th birthday, once at midnight on your 21st birthday. (In some cases, there are one or two other quantum leaps forward.) Nobody thinks that any kind of real transformations overtake people between 11:59:59 p.m. and 12:00:01 a.m. on those dates.


Blogger Pete Mack said...

I dunno. This would make earth's moon into a planet, despite its very different mechanism of formation (via impact, rather than coallescence.) And some of the spherical objects in the solar system are pretty small--just a few hundred miles in diameter. That's not particularly special.

7:59 AM  
Blogger Winston Smith said...


Also: moons orbit planets...why isn't that a sufficient difference?

8:25 AM  
Blogger The Mystic said...

Yeah, the question isn't "is Pluto a moon?" - that's pretty easy to answer.

The question is: "is Pluto qualitatively distinct from other solar orbiting bodies such that it should be considered a planet?"

i.e.: If Pluto is a planet, why not particularly large bodies in the Kuiper belt?

I'd agree that this isn't of too much direct interest, but I think it does bring up a particularly interesting tangential matter:

Given how raging awesome we now know Pluto to be (after New Horizons) - how raging awesome are the who-knows-how-many-others among the trans-Neptunian bodies?

I <3 Pluto. Ever since my hours spent as a child staring at its awesomeness (both factual and hypothetical) in the National Geographic Picture Atlas of Our Universe (I love that book so much), it always seemed like this foreboding last-stop on the way out of our solar system which, one day, might be the last bit of home astroneers see on their way out of town. A dark little hub where, at the right time of day, you might catch a glimpse of what you're leaving behind (as you find yourself sitting atop the methane ice mountain range among the silicon-based life forms which have gained an affinity for people who feed them nummy synthetic snacks that can be purchased at the Pluto Interstellar Hub gift shop, of course).


8:43 AM  
Anonymous Anonymous said...

Unrelated to pluto, but related to groupings and their boundaries, one thing I've found interesting is if you think of them in terms of the complexity theory of their definition. Legal definitions, and the definitions social constructivists insist are the only ones possible, tend to only be what's called O(1) (effectively computable in a constant amount of time, in this case by checking if his age is >= 18. Very easy.). Something like genuinely determining if a child is an adult in fact requires a lot of deliberation about his history, psychosocial development, comparison to the development of his relatives, then using that to get consensus from honest deliberators on whether he qualifies for adulthood; something like that. It's a substantial, non-O(1) decision problem. But that doesn't mean that it isn't well-defined, or unreal. (It just means English majors won't be able to understand it.)

Similarly, something like race, which seems fuzzy and poorly defined if you define it in ways usually available in a 500-word essay, actually is made mathematically precise by cluster analysis on genetic information. There is a clear legal utility for simplification, so a case isn't bogged down in semantics and the court can focus on it's responsibilities. But not recognizing that the simplifications there serve a specific pragmatic purpose, and instead insisting that the only valid definitions behave that way is both weaselly and entirely ignorant of much more interesting ways groups can be constructed.

10:38 AM  
Blogger Winston Smith said...

I'm fond of this romantic Plutoism...or Putonic romanticism, or whatever it is, Mystic...

12:49 PM  
Blogger Winston Smith said...


I've got some computability theory under my belt from grad school...but I don't know anything about computational theories of definitions. Any accessible readings you could suggest?

Like...computational definitions for dummies?

12:50 PM  
Anonymous Anonymous said...

"I've got some computability theory under my belt from grad school...but I don't know anything about computational theories of definitions. Any accessible readings you could suggest?"

So this is just something I'm riffing on to be honest. But, the way you'd think of it is: rewrite the definition in terms of some predicate P, then construct the equivalent decision problem for it, and try to construct an efficient algorithm that solves, or approximates, the decision problem. Obviously in something like determining adulthood, it isn't purely math, but there is a degree of procedure to it, like I said. Is the person a boy or girl, what is the race/ethnicity of the person (different development speeds involved there), is there some history of trauma, is there a consensus achievable that this person is qualified for adulthood. So the complexity is the sum of the complexities of determining gender, ethnicity, searching the history of an individual for the various criteria, and querying social consensus on adulthood, for this pseudo-algrorithm.

Another interesting thing is definition doesn't have to be settled through rational disagreement. What if we were Spartans, and we settled manhood through whether you have taken a life? That's a clear definition, but it isn't decided by a fact about the person, but an action (which then once completed, obviously provides a clear factual basis for adulthood). I think in some sense, existential questions like virtue and manhood are more truthfully settled that way, and it shows an interesting limit of reason itself in those matters.

So there might also be a large set of social categories which are "fuzzy" not necessarily because they are fuzzy, but because we have lost the rituals that prove they are true of you.

1:15 PM  

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