Skepticism is the view that there is no way to prove that objects exist outside of us. Skeptics hold that we can not distinguish between dreams and reality, and therefore what we take to be true can very well be creations of our minds while we are nothing more than a simple piece of matter, such as a brain sitting in a vat that is connected to a machine that simulates a perfect representation of reality for the “brain” to live in.1 In the excerpt “Proof of an External World” from his essay of the same name, G.E. Moore responds to the skeptic’s argument by attempting to prove the existence of external objects. There are four parts to this paper. Firstly, I will explain Moore’s overall argumentative strategy and how he considers his proof to be rigorous and legitimate. Then, I will present Moore’s proof of the existence of an external world. Thirdly, I will discuss the responses that skeptics may have to Moore’s argument and how Moore defends his proof against the these responses. Finally, I will give my opinion on how efficiently Moore defends his claims against the skeptics’ responses.
Moore argues that there exists an external world by giving a simple, believable situation that makes the existence of an external world seem obvious (this will be clarified in the next section). He then demonstrates that it satisfies the three conditions that ensure a rigorous, legitimate proof: that the premiss and the conclusion are different, that the premiss was something he knew was true, and that the conclusion
logically follows from the premiss (GSC 359). Moore even asserts that this kind of proof can answer many different questions that deal with issues that are surrounded by doubt. For example, Moore creates a scenario where there might be three different misprints on a page of a book. Whether the misprints are there or not is the issue that is held in doubt. X says that the misprints are there, while Y says that there are no misprints. X could prove this by turning to the page and physically pointing out the three misprints to Y. The first condition is satisfied because the premiss and conclusion are clearly different; physically pointing out the three misprints and claiming that the misprints exist are two different things. The second condition is satisfied because by pointing out the three misprints, X shows that he knows that the misprints are there. The third condition is satisfied because by pointing to three different misprints and confirming that they are on the page, X can safely say that three misprints on the page exist. Since X has successfully proved that there are three misprints on the page by satisfying these three conditions, if another proof also satisfies these conditions, then that proof must be true. Moore’s proof that the external world exists does satisfy these three conditions.
Moore gives us a simple proof that the external world exists. He proves that two hands exist by holding them up and saying “Here is one...