Putnam, Kripke and Externalism

Introduction

For centuries, writers have posited that there is an ambiguity in the concept of meaning. The terms, extension and intension were introduced in order to combat this ambiguity.

Extension relates to the set of things the term is true of, i.e. ‘rabbit’ is true of all and only rabbit, so the extension of ‘rabbit’ is the set of rabbits[1]. In this paper I will discuss how Externalism is when our beliefs are, in part, outside of us. I f we say that beliefs are in the head we cannot capture how a belief may be about things outside of us. It is obvious that Smith, having a certain belief in part is a matter of how Smith is, otherwise it would not be Smith who has the belief. However, it is a matter of how Smith is, her causal environment and history that plays a major role in determining whether she has one belief of another.

Some of this content is narrow and some is broad. The discussion of this will form the first part of the paper, the second part will be concerned with extension and intension. I will conclude that is impossible for content to be solely narrow or solely broad and that we cannot have intension without extension and vice versa. Both aspects have a part to play in our understanding and use of concepts.

Narrow Content

In Narrow Content the believer’s surroundings do not mater in general for whether the belief if true of false. It matters in the case that If Smith believes there is a tiger nearby then there necessarily has to be a tiger nearby for her to believe this. An example that illustrates well the concept or narrow content is below:

If we took a brain and placed it in a vat and then subjected it to all the same inputs and stimuli as a normal brain in a body would be subjected t, there is a supposition that the brain in the vat would have a very rich life indeed, just the same a brain in a normal person would have. If this is the case, then it points to our mental states being a narrow property of us. If, at this point, out psychology would be the same whether we were a brain in a normal body or a brain in a vat then our psychology would depend only on how you are – not your current environment[2]. Another way to look at this is by considering doppelgangers, this will become quite useful in the next section. A doppelganger is an exact copy of you, you and your doppelganger believe alike. Content cannot be understood in purely internal terms because we apply content using terms that pick out objects around us. It is based, in part, on interactions with our environment. No amount of knowing the internal nature of a person would be able to pick it out without knowing the interactions of the person.

Broad Content

We can show that not all belief content is narrow. If we look at the following example:

Sunburn is a condition of the skin, not of the sun, despite the fact that it would not be a case of sunburn had it not been caused by the sun[3]. Some beliefs obtain their content by due to beliefs and their connection to matters outside of the subject. One reason for this might be that, if we locate beliefs inside the head, it’s difficult, if not impossible, to capture the way a belief might reflect matters outside of us. If we have a belief about a tree, we need to include the tree itself in that belief. Generally, our beliefs are directed to objects around us. If we belief there is tea, that does not capture the arm movement and the hand movement that picks up the cup with the tea in it. Here we can see that behaviour is environment involving.

Does a Psychological State determine extension?

A psychological state does not determine extension. We can show this in the following way.

There is a planet called Twin Earth. For the purposes of this example it is exactly Earth and people speak English. We can suppose That there is a doppelganger of us on Twin Earth. There are a few small differences between the dialect spoken on our Earth and that on Twin Earth. One of these is that the liquid called ‘water’ on Twin Earth is not made up of H20 but of XYZ. XYZ is indistinguishable from water; it behaves like water, it quenches the thirst and it rains XYZ on Twin Earth. If we were to visit Twin Earth, we might suppose that the word for ‘water’ on Twin Earth means XYZ. However, we would not say, ‘on Twin Earth the meaning of the word “water” is XYZ, that is unless all speakers on Earth know of XYZ. If a spaceship form Twin Earth visited Earth they might say that the word ‘water’ has the same meaning on Earth and on Twin Earth. This would be corrected eventually, and the report back would be: On Earth the word “water” means H20.

Let us now look at the time where chemistry was not developed. The typical Earth dweller did ot know that water consisted of H20 and the typical Twin Earthian did not know that ‘water’ consisted of XYZ. If we take, for example, Horace and Henry, Horace lives on Earth and Henry lives on win Earth. In the times before chemical compostiions were known we could assume that there is no belief that Horace had about water that Henry did not have about ‘water’. Horace and Henry are exact duplicates yet understand the term ‘water’ differently even though they were in the same psychological state. Tus the term ‘water’ is not a function of the psychological sate of the speaker by itself.

Suppose in the following example I can’t tell an Elm from a Birch Tree. We would still say that the extension of ‘elm’ is the same for me as it is for most people, and that the set of Birch trees is the extension of Birch for all of us. So ‘elm’ has a different extension to ‘birch’ in both our idiolects. If on Twin Earth my doppelganger has the words ‘elm’ and ‘birch’ switched, his psychological state is the same as mine but he means ‘birch’ when he says ‘elm’[4].

When we discuss the concept that meaning has an intension aspect and an extension aspect to it we can address the division of linguistic labour

Linguistic Labour

The extension of a term is not fixed by a concept in the speaker’s head because the extension is determined socially. So, we cannot identify a meaning solely with either intension or extension. Where intension is the speakers concept and extension is the socially determined aspect of the meaning. If we revisit the ‘elm’ and ‘birch’ example, we could not say that ‘elm’ and ‘birch’ have the same meaning on Earth and on Twin Earth even if my doppelganger’s concept of (or an ‘elm’ as he calls it) is identical to my concept on an elm. We would say that my doppelganger and I mean something different when we state the workd ‘elm’ but that is not a reflection of our psychological states.

Extension

If we look solely at the concept of extension and we say that a speaker only knows that a ‘tiger’ has a set of physical objects as its extension, and he can use ‘tiger’ in sentence, albeit in a restricted manner i.e. “tigers take up space” we could not conclude that that speaker knew the meaning of the word tiger.

This is because, when we say someone has acquired a word, we take that to mean that the speaker knows the meaning of the word i.e. he has identified the right concept for the word or is in the right psychological state with respect to it. For example, if the Speaker were to see a tiger he would feel fear and want to run away. The speaker has to know something about what we class as a together in order to be able to use the word ‘tiger’ effectively in communication. We would expect the speaker to know what a tiger looked like and be able to tell it apart from a lion. If he knows a tiger is a large type of cat we might say he partially understand the meaning of the word.

So here we can see that in order to obtain a meaning of a word or to acquire a word we have to have the elements of intension and extension. One without the other does not work. Intension allows us to be in the right psychological state to understand the word and extension allows us to use the word within a community.

Conclusion

If we take meaning to have a vector, then part of it is an extension so in part its true meaning is an extension. Therefore, meaning can’t be identified with extension or intension if intension is the speakers concept. As we can see above, Putnam and Jackson make strong arguments for externalism. I do not think that one can view the world in terms of extension only or in terms of intension only. Therefore, I find the arguments above provide another essential part of the discussion around belief. I am inclined to accept Putnam’s argument that there is intension and extension in a belief and this would form a vector, i.e. a concept made up of

[1] Here I do not propose to go into set theory, or the mathematical theory of fuzzy sets.

[2] Braddon-Mitchell, D., 2007. The philosophy of mind and cognition.

[3] Braddon-Mitchell, D., 2007. The philosophy of mind and cognition.

[4] Putnam, H., 1975. Mind. Language, and Reality, 2.