Skepticism

Descartes' Response (Against Skepticism)

- "I think, therefore I am.": cannot doubt that he exists since he is the one doing the doubting - He knows this because he "clearly and distinctly" perceives it - Clear and distinct perception (an immunity to doubt) is a mark of truth

Initial Skeptical Challenge (for skepticism)

- Can we ever have knowledge? Skeptics say we can never have knowledge of the external world - based on claim that knowledge requires certainty - if your belief could be mistaken, it is not knowledge - if your belief is knowledge, you must be absolutely certain that it is true - knowledge requires certain justification

Contextualism (Against Skepticism)

- How much justification for a belief is required for knowledge? - The standards for applying some terms varies depending on the context - You can have knowledge in some context but not others - Whether you know something changes from context to context

Do skeptics claim to know that the premises of their skeptical arguments are true? (Skepticism is self-refuting)

- If they do "know" then their argument is inconsistent. How do they know that they aren't being deceived into thinking that the premises are true? - If they don't then why should we take their argument seriously? After all, they don't know whether their premises are true

Do skeptics live their lives in accordance with their skepticism? (Skepticism is self-refuting)

- If they really believe that they have no knowledge about the world, then it should make a difference as to how they live ex.) Why would the stop and converse with people, step out of the way of traffic, etc. - Not doing so implies that they believe that other people exist, and that traffic is dangerous, etc.

Fallibilism (Against Skepticism)

- Knowledge requires having good reasons for believing that a claim is true, but does not require being certain that the claim is true - a justified belief doesn't need to be a certain belief

Revised Skeptical Challenge

- Not based on claim that knowledge requires certainty - We don't have any justification for ordinary beliefs about the external world 1.) Our evidence does not provide a better explanation for ordinary external-world claims than to believe rival skeptical hypotheses (demon, vat, etc) 2.) If one's evidence does not provide better reason to believe one hypothesis than to believe some rival hypothesis, one is not justified in believing that hypothesis 3.) People are not justified in believing ordinary external-world claims

Inference to the Best Explanation (Against Skepticism)

- The evidence from our senses best explains that the ordinary world is real, than by any of the skeptical hypotheses - Simplicity: all else equal, a simpler explanation is better - Skeptical hypotheses are like conspiracy theories: needlessly complicated

Immediate Perceptual Justification (Against Skepticism)

- We are justified in believing things as they seem unless we have defeating evidence that shows that they are not as they seem - "Innocent until proven guilty" ex.) It seems as if the fire is real--and we have no reason to believe in a skeptical hypothesis instead--so we are justified in believing that the fire is real

Epistemological Conservatism (Against Skepticism)

- We are justified in retaining our beliefs as long as our evidence does not provide better support for some other rival belief ex.) Stick with your current relationships unless making a change would be an improvement ex.) We are justified in believing that the fire is real even if rival skeptical hypotheses provide equal support by the evidence--just because it is the belief that you already have

Descartes' Response: Circulatory Objection (Against Skepticism)

- We are sure that what we clearly and distinctly perceive is true only because God exists - But we can be sure that God exists only because we clearly and distinctly perceive so - Therefore, we can only be sure that God exists if we are able to be sure that what we perceive to be clear and distinct is evidently true - This argument begs the question

Reliabilism (Against Skepticism)

- Whether our beliefs about the external world are justified doesn't depend on our evidence - It depends on whether those beliefs were produced by a reliable belief-forming process - If forming beliefs based on sensory experiences is a reliable belief-forming process, then our beliefs about the external world are justified even if we lack evidence for them - Process is reliable > beliefs are justified > knowledge of the external world

Evidentialism

- a belief is justified as long as one has evidence for it

Reliabilism Counterexamples/Cases

1.) Counterexample: cases of reliable belief-forming processes but no evidence ex.) Clairvoyance 2.) Counterexample: cases in which two people have the same evidence but use different belief forming processes ex.) Actually running vs brain in VAT 3.) The Generality Problem: what counts as the process that produces a particular belief? How general are the processes?

Responses Against Skepticism

1.) Descartes' Response + Circularity Objection 2.) Skepticism is Self-Refuting 3.) Moore's Argument 4.) Fallibilism

Skepticism is Self-Refuting (Against Skepticism)

1.) Do skeptics claim to know that the premises of their skeptical arguments are true? 2.) Do they live their lives in accordance with their skepticism?

Moore's Argument (against Skepticism)

1.) I know that I have two hands 2.) If I know that I have two hands, then skepticism about the world is false 3.) Therefore, skepticism about the world is false