Posted by alexandra_k on August 17, 2005, at 17:41:51
In reply to Re: the meaning of meaning, posted by alexandra_k on August 17, 2005, at 17:25:19
I am getting there... I am getting there...
So... The thought is that initially we picked out samples of water by its qualitative properties. We knew to dub something water when it appeared to be 'that watery stuff'. The clear liquid that falls from the sky, fills the lakes, is drinkable, potable etc etc. Thats how we identify whether something is correctly called 'water' or not.
But then on with the march of science... And the scientists tell us 'that watery stuff that falls from the sky etc has a common essential nature and that essential nature is that it is H2O.
And so the scientists fix the reference of the term. The thought is that now we know the essential nature of the stuff that we initially refered to via its qualitative properties. If the qualitative properties come apart from the essential properties (as they do most clearly on twin earth) then the essential properties take priority with respect to reference.
So: Initially we go via qualitative properties. Scientists discover a correlation between qualitative properties and essential properties. An identity claim is made (Water = H2O) and from thereon the essential properties fix the reference.
Kripke maintains that identity claims are necessary. Once we discover a correlation on the actual world and make an identity claim then that identity claim is true on all possible worlds.
Now what is interesting...Initially we identify mental states like pains, tickles, emotions etc by their qualitative properties. Then on with the march of science and scientists discover (or more properly WILL discover) correlations between certain neural patterns and qualitative states. The scientists want to make an identity claim 'mental state x = brain state y'. Now if the identity claim is right then this identity claim is necessary. What that means is that mental state x would = brain state y across all possible worlds. And when the qualitative properties come apart from the essential properties then the dennotation follows the essential properties.
And this is a problem quite a few people struggle with...
Kripke says that clearly it is false that mental states are identicle to brain states across all possible worlds. Clearly it is possible for beings without brains to have mental states. Thus he maintains that the identity claim between mental states and brain states is necessarily false.
Hmm. Hrm...
The trouble is... Knowing whether we have an identity claim or not to start with. If we DO have an identity then it is true in all possible worlds... If we DO NOT have an identity then it is false in all possible worlds... I think you are also allowed contingent identity (true on some worlds and false on others) - but I'm not sure whether that counts as identity...
Any way... Going counterfactual (considering other possible worlds) isn't like observing these possible worlds through a telescope and seeing what is there (credit to Kripke). It is an intuition pump. To get us thinking about what is and is not possible. And the trouble is that it is perfectly possible for rational people to disagree. So the thought experiments aren't terribly rationally persuasive much of the time (nobody is going to change their mind based on them). It is very controversial what if any use 2 d modal logic is...
I think... That sometimes... Actually most times... The qualitative properties are what interests us. We are interested in essential properties only insofar as there is some kind of lawful connection between essential properties and qualitative properties.
The business of science is to explain and predict things on the qualitative level. To explain our experience of the world.
But thats just my opinion.
And I don't really know what I'm talking about...
poster:alexandra_k
thread:541758
URL: http://www.dr-bob.org/babble/write/20050807/msgs/543133.html