Skepticism

Question 1

what is local Skepticism?

Answer 1

The view that we cannot have knowledge in a specific area or branch of knowledge, such as the external world or other minds.

Question 2

What is Global Skepticism?

Answer 2

Global philosophical skepticism is the view that we cannot have any knowledge whatsoever, as all beliefs—including those based on reason or sense experience—can be doubted.

Question 3

Descartes’ Method to global skepticism

Answer 3

We should try to doubt all of our beliefs.
We should use the most extreme arguments we can think of to do this.
Beliefs that can be doubted are not justified and so cannot be counted as knowledge.
This doubt is being used for a positive purpose - it is being used as a method for discovering what we know

Question 4

Descartes’ First wave of doubt

Answer 4

If my sense deceive me, then the cannot and should not be used as a source of knowledge.
My senses do and can deceive me
Therefore I shouldn’t trust my senses as a source of knowledge

Question 5

Descartes’ Second wave of doubt

Answer 5

In order to have perceptual knowledge of mind-independent reality, I need to know that I am not dreaming now.
I cannot know that I am not dreaming as all perceptual experiences can happen in a dream.
Therefore dreams are subjectively indistinguishable from accurate perceptual experiences.
Therefore I cannot have perceptual knowledge of mind independent reality.

Question 6

Descartes’ Third wave of doubt

Answer 6

In order to have perceptual knowledge of mind-independent reality, I need to know that I am not dreaming now.
I cannot know that I am not dreaming as all perceptual experiences can happen in a dream.
Therefore dreams are subjectively indistinguishable from accurate perceptual experiences.
Therefore I cannot have perceptual knowledge of mind independent reality.