The Arthritis Case
If a man falsely believes he has arthritis in his thigh, what exactly was he believing, and who gets to decide?
Tyler Burge introduced this case in 1979 to show that the content of mental states depends not just on what's inside an individual's head but on the linguistic community they belong to. It is the clearest argument for social externalism about mental content.
Burge, T. (1979). Individualism and the Mental. Midwest Studies in Philosophy, 4(1), 73–121.
The case
A man has visited doctors and been told he has arthritis. He accepts this. One day he tells his doctor that his arthritis has spread to his thigh. The doctor corrects him: arthritis is a condition of the joints; it cannot occur in the thigh.
The man had a false belief. But what was the content of that belief? He believed he had "arthritis in his thigh." Since arthritis cannot occur in the thigh, no such condition exists. Yet something went wrong in his thinking, and we want to describe what.
Social externalism
Burge's argument turns on a comparison. Imagine a counterfactual version of this man, physically and mentally identical, but living in a community where "arthritis" is used more broadly to include rheumatic conditions in muscles. In that community, the man's belief would be true: he does have what they call arthritis in his thigh.
Same internal states. Different belief content. Burge calls this social externalism: the content of what you believe is partly fixed by the linguistic practices of your community, not just by what's happening inside you. The word "arthritis" in English means what it means because of how medical communities and ordinary speakers have collectively shaped its use.
The objection and Burge's reply
The most natural objection is that we should simply say the man has a different concept, call it "tharthritis," that he has confused with arthritis. On this view, his belief is internally coherent; he just has idiosyncratic terminology. Nothing surprising follows.
Burge's reply is that this redescription is doing a lot of covert work. When the man goes to the doctor, uses the word in conversation, reads about the disease, he is participating in the use of the English word "arthritis." His thought inherits its content from that participation. To say he secretly has his own private concept is to assume exactly what's in dispute: that content is settled internally, before social practice enters. The case is designed to show that assumption is wrong from the start.
Discussion questions
- If you have always used a word incorrectly but everyone around you understood what you meant, were you wrong?
- Do you think words mean what you intend them to mean, or what your community has decided they mean?
- Can you think of a word whose meaning has shifted so much it now means almost the opposite of what it originally meant?
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