Definitions

Skepticism: The attitude of doubting or questioning claims, especially those that are widely accepted.

Epistemology: The study of knowledge - how we know what we know.

Justification: Having good reasons or evidence for believing something.

Certainty: Being completely sure about something, with no possibility of being wrong.

What is Skepticism?

Skepticism is the practice of questioning claims and demanding evidence before accepting them as true. It's not about being negative or cynical, but about being careful and thoughtful about what we believe.

The Skeptical Attitude

A skeptic asks: "How do you know that?" and "What evidence supports this claim?" before accepting any belief.

Not the Same as Denial

Skepticism is not the same as denying everything. It's about being open to evidence and changing your mind when the evidence warrants it.

Types of Skepticism

Methodological Skepticism

Using doubt as a method to find truth. Descartes used this approach - he doubted everything he could doubt to find what was absolutely certain.

What did Descartes find?
Philosophical Skepticism

The view that we cannot have certain knowledge about anything, or at least about most things.

How far does this go?
Scientific Skepticism

Questioning extraordinary claims and demanding extraordinary evidence. This is the approach used in science.

Arguments for Skepticism

The Problem of Induction

We can't prove that the future will be like the past. Just because the sun has risen every day doesn't guarantee it will rise tomorrow.

What does this mean for science?
The Problem of Other Minds

How do we know that other people have minds and experiences like we do? We can only observe their behavior, not their inner thoughts.

The Brain in a Vat

How do we know we're not just brains in vats being fed false experiences by a supercomputer? We can't rule this out with certainty.

Problems with Extreme Skepticism

Self-Refuting

If we can't know anything, then we can't know that we can't know anything. This creates a logical contradiction.

Practical Impossibility

We can't live our lives without making assumptions. We have to act as if the world exists and other people have minds.

What's the practical solution?
Paralyzing

If we doubt everything, we can't make decisions or take action. Life requires us to act on our beliefs.

Conclusion

Skepticism is a valuable tool for critical thinking, but it can be taken too far. The key is finding the right balance between questioning and accepting reasonable beliefs.

The Middle Way

We should be skeptical of extraordinary claims and demand good evidence, but we can still have justified confidence in ordinary, well-supported beliefs.