Editing Internalism and externalism (section)

=== As a response to skepticism<!--Linked from 'Semantic externalism'--> ===
In responding to [[Philosophical skepticism|skepticism]], [[Hilary Putnam]] (1982<ref name="Putnam, H. 1981">Putnam, H. (1981): "Brains in a vat" in Reason, Truth, and History, Cambridge University Press; reprinted in DeRose and Warfield, editors (1999): Skepticism: A Contemporary Reader, Oxford UP.</ref>) claims that [[semantic externalism]] yields "an argument we can give that shows we are not [[brain in a vat|brains in a vat]] (BIV).  (See also DeRose, 1999.<ref name="DeRose">DeRose, Keith (1999) "Responding to Skepticism", Skepticism: A Contemporary Reader.</ref>) If semantic externalism is true, then the meaning of a word or sentence is not wholly determined by what individuals think those words mean.  For example, semantic externalists maintain that the word "water" referred to the substance whose chemical composition is H<sub>2</sub>O even before scientists had discovered that chemical composition.  The fact that the substance out in the world we were calling "water" actually had that composition at least partially determined the meaning of the word.  One way to use this in a response to skepticism is to apply the same strategy to the terms used in a skeptical argument in the following way (DeRose, 1999<ref name="DeRose" />):

{{Blockquote|Either I am a BIV, or I am not a BIV.<br/>
If I am not a BIV, then when I say "I am not a BIV", it is true.<br/>
If I am a BIV, then, when I say "I am not a BIV", it is true (because "brain" and "vat" would only pick out the brains and vats being simulated, not real brains and real vats).<br/>
---<br/>
My utterance of "I am not a BIV" is true.}}

To clarify how this argument is supposed to work:  Imagine that there is brain in a vat, and a whole world is being simulated for it.  Call the individual who is being deceived "Steve."  When Steve is given an experience of walking through a park, semantic externalism allows for his thought, "I am walking through a park" to be true so long as the [[simulated reality]] is one in which he is walking through a park.  Similarly, what it takes for his thought, "I am a brain in a vat," to be true is for the simulated reality to be one where he is a brain in a vat.  But in the simulated reality, he is not a brain in a vat.

Apart from disputes over the success of the argument or the plausibility of the specific type of semantic externalism required for it to work, there is question as to what is gained by defeating the skeptical worry with this strategy.  Skeptics can give new skeptical cases that wouldn't be subject to the same response (e.g., one where the person was very recently turned into a brain in a vat, so that their words "brain" and "vat" still pick out real brains and vats, rather than simulated ones).  Further, if even brains in vats can correctly believe "I am not a brain in a vat," then the skeptic can still press us on how we know we are not in that situation (though the externalist will point out that it may be difficult for the skeptic to describe that situation).

Another attempt to use externalism to refute skepticism is done by [[Anthony Brueckner|Brueckner]]<ref>{{cite book
 | first = Anthony
 | last = Brueckner
 | chapter = Semantic Answers to Skepticism
 | title = Skepticism: A Contemporary Reader
 | pages = 43–60
 | publisher = Oxford University Press
 | year = 1999
 | location = Oxford
}}</ref> and [[Ted A. Warfield|Warfield]].<ref>Warfield, Ted A. Skepticism (1999, ed. with Keith DeRose, Oxford, 1999)</ref> It involves the claim that our thoughts are ''[[intentionality|about]]'' things, unlike a BIV's thoughts, which cannot be ''about'' things (DeRose, 1999<ref name="DeRose"/>).