Posted by special_k on April 16, 2006, at 9:37:09
In reply to Venus calling » 838, posted by zeugma on April 14, 2006, at 19:23:26
> if hesperus is phosporus it is so, a priori.
ooh. what do you mean by a priori?
i thought a priori / a posteriori were epistemic notions. something that is knowable a priori is something that that can be known on the basis of conceptual analysis, whereas something that is knowable a posteriori is something that can be known on the basis of looking to the world. some things might only be knowable a posteriori (that water=h2o and that... hesperous is phosperous). some other things might only be knowable a priori (though testimony excepted i guess) like mathematics and logic. mathematics and logic seem to be knowable both a priori (when one does a deduction) and a posteriori (when one believes the answer the teacher gives you).> We are talking about the referents of hesperus and phosphorus. but '''hesperus' and 'phosphorus' share the same referent'' is a contingent fact of the language.
ooh. do you mean we could have said 'gavagai' and pointed to the sky instead of saying 'hespherous'? the word / referent relation is contingent, yup... but given that we pointed and said 'hesperous' and pointed and said 'phosperous' it turns out that hesperous (the object pointed to) is phosperous (the object pointed to). and that latter point (about x and y being the same object) is thought to be a matter of necessity (given that they are identical in the acutal world hesperous - the object - is identical to phosperous - the object - in any world in which the object exists.)
> so is "'hesperus' is hesperus." That is not an a priori truth on any account.
i think the idea is that 'x is identical to x' is an analytic / a priori truth that we can grasp from the armchair.
> hmm... suppose Hesperus were like Pegasus.... must one believe that Pegasus is Pegasus, if Pegasus does not exist?
er... yes non existent objects (and negative existentials - 'santa claus does not exist') were two other motivations for fregean senses / primary intensions. personally... i think pegasus exists as a primary intenstion / an idea / a description. much like sherlock holmes (and of course it is TRUE to say sherlock holmes lives in baker street even though there is no such thing as sherlock holmes in the world there is such a thing as sherlock holmes the fictional character and yup that is how the story goes...)
> but hesperus is phosporus necessarily, if we are talking about h and p de re.er... de re (object). de se (i forget... idea?). de dicto ('hesperous'). is that like dog (object) DOG (concept) and 'dog' (word). yep the object picked out by 'hesperous' and the object picked out by 'phosperous' are the same object in the actual world (we had to look to see so this is a posteriori rather than a priori we couldn't have figured it from our armchair). any described scenario in which the object picked out by 'hesperous' and the object picked out by 'phosperous' is not the same object... the appropriate way to describe the world is to describe it as one in which either hesperous or phosperous or perhaps both don't exist.
> I can easily imagine hesperus and phosphorus as being separate objects.
you can imagine (a priori) a world in which the object picked out by 'hesperous' and the object picked out by 'phosperous' were actually different objects. sure you can. thats why the a posteriori discovery that hesperous= phosperous was a significant astronomical discovery...
> 'a priori' and 'a posteriori' are relative terms,
are they solely epistemological terms or do they come up in other contexts? are they about ways of knowing...
> The 10th planet, or whatever it is, is afflicted by debate about what a 'planet' is. the fact is that since we lived on one, we didn't need more than an ostensive definition of the term 'planet.'
yeah that is funny. i'm thinking planets aren't natural kind terms... maybe they are more like 'large rock' which isn't a natural kind term either...
> yes, location is everything.yeah. some people like the idea of relativised possible worlds. so we can consider some possible worlds as actual from their point of view. (so we can evaluate a twin earthians claim 'water is h2o' as false in her context of utterance). other people say utterances should be evaluated in the context of the actual world. maybe it depends on how seriously you take possible worlds...
> the scenarios don't 'really' exist, if you want my uneducated opinion.
yeah. that is the idea. possible worlds exist (if Lewis is to be believed). but the thought is that scenarios... are just consistent descriptions (ie descriptions which aren't ruled out a priori as desctiptions of a possible world because they are consistent). but then we figure out stuff about the way this world is... and we realise that while twin earth might be a consistent desctiption... twin earth is not hte acutal world.
> I could have been abducted to twin Earth when I left the apt., and my jacket is spattered with unusual molecules. This would be surprising (but in New York anything can happen). If investigated it would be called something other than 'water.' 'This stuff here' would express a novel Fregean sense, when used in this context; note that I might not have access to this bit of sense (no priviliged access to senses- no wonder we spout so much nonsense habitually). I suppose this is basic externalism.
why the same fregean sense?
would they have the same primary intenstion?
if the primary intenstion is 'watery stuff' then the watery stuff on earth and twin earth has the same primary intension / sense.
it is just the referent that is different.
but externalism seems to be infecting primary intensions :-(
er... on a slightly related note... i have been hearing a little about 4d objects... and if that is right... if that is right...
that an object is not wholly present but a time slice is wholly present. and the time slice is related to the next time slice is related to the next time slice and the object is the whole 4d space-time worm... then objects don't change... er...
anyway... if this is right...
i think hesperous doesn't = phosperous (hence they are not identical necessarily)
i think hesperous is 'venus in the morning'
and phosperous is 'venus in the evening'
(hope i got them the right way around)
and venus... is the greater object. they are time slices of venus...what do you reckon?
poster:special_k
thread:618106
URL: http://www.dr-bob.org/babble/write/20060331/msgs/633791.html