Chapter 9 - Descartes: Doubt and Certainty

From Vaughn Textbook, Topic: The Pursuit of Knowledge; Plato's Rationalism; Descartes' Doubt; and Descartes' Certainty

What is the main question in epistemology?

Whether we have propositional knowledge, and, if we do, how much we have

What are the three conditions of propositional knowledge?

1. You must believe it

2. It must be true

3. You must have good reasons for believing it

What does Plato believe is the source of our knowledge?

Reason

What are the two worlds Plato believes make up reality?

• Physical world → accessed through sense experience

• Nonphysical, changeless world of genuine knowledge → accessed through reason

In what world does Plato believe the Forms reside?

The nonphysical world

What are the forms?

Perfect conceptual models for every existing thing

In what way does Plato believe in innate knowledge?

He believes that knowledge of the Forms is already present at birth, inscribed in our minds in a previous existence

Why does Descartes initially doubt beliefs derived from sense experience?

He makes two argument, the dream and evil genius arguments:

• Dream → there are no certain indications by which we may clearly distinguish wakefulness from sleep

• Evil genius → an evil genius or god may have set out to deceive us and could delude every thought, meaning you cannot know anything you think you know

How does Descartes dissuade himself of scepticism?

He cannot possibly doubt that he exists, for if he can have this doubt, he must exist → ‘puisque je doute, je pense; puisque je pense, j’existe’

What principle of knowledge acquisition does Descartes posit?

If he perceives something clearly and distinctly, he must know it with certainty → in his mind he has a notion of perfection, which must come from a perfect cause, which he says is a perfect God — a God that wouldn’t allow him to be deceived

What is the wax thought experiment?

Descartes uses it to argue for rationalism: if a wax shape melts, our senses tell us it is a different object, but through rational intuition our minds understand it remains a piece of wax → relying only on sense experience would tell us that the original wax no longer exists

What is epistemology?

The philosophical study of knowledge

What is propositional knowledge?

Knowledge of a proposition, i.e. a statement that is either true or false

What is scepticism?

The view that we lack knowledge in some fundamental way

What is a priori?

Knowledge gained independently of or prior to sense experience

What is a posteriori?

Knowledge that depends entirely on sense experience

What is knowledge gained independently of or prior to sense experience?

A priori

What is knowledge that depends entirely on sense experience?

A posteriori

What are rationalists?

Those who believe that some or all of our knowledge about the world is gained independetly of sense experience

What are empiricists?

Those who believe that our knowledge of the world comes solely from sense experience

Why was Plato a rationalist?

He, like many relativists, thought that our sense experiences were unreliable (e.g. tastes being good or bad for different people) but instead said we could derive knowledge from reason

Why did Plato believe we could have knowledge?

We can identify false beliefs and grasp mathematical, conceptual, and logical truths → we have objective truths that are discovered

What argument can be made to support innate knowledge?

That we can conceive of the idea of perfection, even though we have never truly encountered a perfect object

How do empiricists counter the idea of innate knowledge?

They say our mind has cognitive capacities to learn certain concepts, but that these are far from having actual innate knowledge

What movie is similar to Descartes’ early scepticism?

The Matrix → Neo living in a simulation that he can’t help but take as real resembles Descartes’ doubt that he could distinguish reality from unreality

What is the principle of clarity and distinctness?

The principle in which Descartes tries to demonstrate that God exists that has been criticised for committing the begging the question fallacy → his pattern of argument has even become known as the Cartesian circle