fix typo

content/blog/2023-05-02_physicalism/index.md

@@ -35,7 +35,7 @@ First, he says that we can be **certain** of our own existence and we can never
 
 Alright. That's wonderful, Descartes thinks. In fact, he claims he's *proven* that he's right. He's content to say that given that argument, there can be no doubt as to the nature of mind as separate from body. But he also gives another argument, just to drive the point home. He says that body, material substance, is fundamentally different from mind because it is *extended*. By this he means that it has shape and size, whereas thoughts are completely different. To depart a little bit from Descartes' simplistic understanding of physics (by the standards of our time), he's saying that any physical thing has physical properties, but thoughts do not, and therefore they must be of a totally different nature.
 
-### Part Three: My Destruction of the Exntension Argument
+### Part Three: My Destruction of the Extension Argument
 
 Here's the part where instead of summarizing other people, I say something original. Kinda.