Moore, “Proof of an External World”

What is the main goal of G. E. Moore’s “Proof of an External World”?

The main goal of Moore’s “Proof of an External World” is to prove that external objects exist, meaning that objects independent of the mind—such as hands, trees, and tables—are real and not merely mental constructs.

What is Moore’s basic “hand proof” for the existence of external objects?

Moore raises his hands and states: “Here is one hand” and “Here is another hand.” Since hands are external objects, their existence proves that external objects exist, and therefore that an external world exists.

What are the three conditions Moore says any proof must satisfy?

1. The premises must be different from the conclusion.

2. The premises must be known to be true.

3. The conclusion must follow logically from the premises.

Moore argues his hand proof satisfies all three conditions.

How does Moore use the “misprints in a book” example to defend his hand proof?

Moore compares pointing to misprints in a book (“There is one misprint here, here, and here”) to pointing to his hands. He claims both examples satisfy the criteria of a good proof: pointing shows the existence of misprints just as pointing shows the existence of hands.

What premise does Moore claim to know in his hand proof?

Moore claims to know the premise: “Here is a hand.” He treats this as a piece of common-sense knowledge.

What conclusion does Moore draw from identifying his hands?

Moore concludes that since hands are external objects, and since they exist, an external world also exists.

Why do many philosophers reject Moore’s hand proof?

hilosophers reject it because they want Moore to prove the premise (“Here is a hand”) by answering deeper skeptical questions such as:

• How do you know you’re not dreaming?

• How do you know your senses aren’t deceived?
  They demand a general epistemological argument, not a simple demonstration.

What is the dreaming objection raised against Moore?

The dreaming objection claims that Moore cannot prove he is not dreaming right now, since dreams can feel like waking experiences. If he can’t prove he’s awake, then he cannot know he has hands.

How does Moore respond to the claim that he cannot prove he is not dreaming?

Moore concedes he cannot prove he is not dreaming, but insists he still knows he is awake. For Moore, knowledge does not require proof, so he can know he has hands even without refuting the skeptical hypothesis.

What distinction does Moore make between knowing and proving?

Moore argues that you can know something even if you cannot prove it. Proof demands explicit justification; knowledge does not. For example, you know your name or that you ate breakfast today, even though you can’t logically prove those facts.

How does Moore apply the knowing/proving distinction to his proof of the external world?

He claims:

• He knows he has hands.

• He cannot prove he is not dreaming.

  • But his lack of proof does not undermine his knowledge.
    Therefore, the hand proof remains a legitimate proof.

What was Kant’s position regarding knowledge of the external world, according to Moore?

Kant believed we must have a philosophical proof or argument (e.g., the transcendental deduction) before claiming knowledge of the external world. Knowledge requires a theoretical framework.

How does Moore respond to Kant’s demand for a philosophical proof of the external world?

Moore rejects Kant’s requirement, arguing that he already knows external objects exist (e.g., his hands) even without a philosophical demonstration. Common-sense knowledge outweighs complex philosophical skepticism.

What is Moore’s final claim about his knowledge of the premises of his proof?

Moore insists that he genuinely knows his premises (“Here is a hand”), even if he cannot prove them. So objections that demand proof of the premises are misguided.

What is the core skeptical challenge Moore must address?

The challenge is that he might be mistaken about having hands because he cannot rule out skeptical scenarios such as:

• Dreaming

• Hallucinations

• Evil demon deception

• Simulation hypotheses

Moore must show he can know external objects exist despite these possibilities.

What is the core idea behind Moore’s “common-sense philosophy”?

Moore believes ordinary beliefs like “I have hands,” “I am standing here,” and “The earth existed long before I was born” are more certain than abstract skeptical arguments. Common sense outweighs philosophical skepticism.

How does Moore flip traditional philosophical skepticism?

Instead of doubting ordinary beliefs until proven, Moore takes ordinary beliefs (e.g., “I have hands”) as more certain than skeptical hypotheses. Thus, skepticism is less credible than common-sense knowledge.

What general epistemological position does Moore’s argument support?

Moore’s argument supports foundationalism rooted in common-sense facts: certain basic perceptual beliefs are known without requiring further proof.

How might someone argue Moore begs the question in his hand proof?

Critics argue Moore assumes what he needs to prove—namely, that perceptual beliefs (like “here is a hand”) are trustworthy. Since the skeptic disputes perception’s reliability, using perception as evidence seems circular.

How does Moore reply to the charge that his proof is circular?

Moore denies circularity by stating that he is not trying to prove perception is reliable; he is only showing that given the knowledge he has (e.g., “here is a hand”), the conclusion follows. He is presenting a proof, not an explanation of how he knows.

What is Moore’s methodological stance regarding proof and explanation?

Moore believes a philosophical proof does not need to explain how knowledge is possible. It simply needs true premises and valid reasoning. He refuses the skeptic’s demand for a deeper epistemic theory.

How does Moore’s logic apply to the claim “I know my phone exists”?

Moore would argue you know your phone exists by perceiving it (“Here is my phone”). Even if you cannot prove you’re not dreaming or hallucinating, your knowledge stands because knowledge does not require proof.

What does Moore openly admit about skeptical hypotheses?

Moore admits he cannot prove that skeptical hypotheses (e.g., dreaming) are false. But this inability does not undermine his claim that he knows external objects exist.

Why is Moore’s “Proof of an External World” philosophically significant?

It is significant because it shifts epistemology toward common sense, challenges skepticism without refuting it, and argues that knowledge can be independent of proof, influencing analytic philosophy and ordinary language philosophy.

What is Moore’s core claim in one sentence?

Moore’s central claim is: “I know external objects exist, because I know I have hands, even though I cannot prove I am not dreaming.”