[ExI] Pure Philosophy Dispute: Are Categories Objective?

[Lee Corbin]

Stathis writes


> Lee wrote:
> 
>> Can you imagine an alien intelligence that reached our
>> solar system that would not place between 8 and maybe
>> 20 objects in orbit around our sun in a special category
>> that we might as well call "planets"?  They would
>> definitely see that about out to 2 AU there are four
>> outstanding real objects (Mercury, Venus, Earth, and
>> Mars) that objectively existed and were categorically
>> distinct from other debris orbiting the sun.  It's hard
>> to believe that any typical evolutionarily derived
>> intelligence that managed to reach our solar system
>> would be incapable of so distinguishing these objects,
>> and I say that it is *no* coincidence that they formulate
>> almost exactly the same categorization that we have.
>> Why?  Because that categorization is objective, and
>> does *not* merely a result of processing in the minds
>> of "observers".
> 
> How could you be sure of that?

Can't be 100% sure, of course, but I'd lay very strong odds.

> If they are gas giant dwellers they might just lump the rocky planets
> in with the asteroids and specks of dust. Look at the trouble we
> have had classifying Pluto, Eris and Ceres (which, following Amara's
> links, I discovered was considered a planet between Mars and
> Jupiter for a number of decades after its discovery).

The aliens of which you speak may have no interest in anything
but gas giants, and have no time for other speculations. But 
supposing that the tendency to be curious about natural phenomena
having ostensibly nothing to do with our survival is not confined to
our species, but rather is indicative of the most successful and
literally out-going species, then they'll have not a few astrophysicists
and astronomers among their race. They *will* see the asteroid
belt as a type of clumping of matter quite different from Mars
and from the Earth, in their respective orbital areas. They'll
certainly see the gas giants in a separate category (according
to your scenario). 

But yes, at some point the universe is not quite so insistent, and
I suppose that they might have some trouble with Sedna, Pluto,
and the rest of the non-planets way out there.

Lee