Philo

• What is Descartes method of doubt?

  At the beginning of Meditation 1, Descartes outlines a 'method of doubt' or way of thinking which he seeks to employ throughout the book.

  1. He will examine the foundations of all of his knowledge.

  2. Whole categories of knowledge, not individual claims, will be questioned.

  3. This will free him from relying upon less than certain beliefs.

  4. Particularly empiricism.

  5. If successful he will establish a foundation for knowledge that is beyond doubt.

  6. It will only be necessary to do this once in a lifetime.
• Criticism Method of doubt

  Some people say Descartes didn't really doubt - he already knew what he was trying to prove.

  Hume said it is incorrect to understand knowledge as certain. Even our most secure knowledge is probable.
• Deceiving God


  This argument is designed to question the certainty of a priori knowledge.

  For example, were there a deceiving God, this being could trick us about mathematical truths.

  Descartes notices that such a being could deceive him about the existence of the entire physical world.

  Descartes concludes that the foundations for all his knowledge are undermined by the possibility that God might be deceiving him.
• Evil demon argument


  Descartes' conclusion that, by the end of the Method of Doubt, he can raise a doubt about every single one of his former beliefs.

  Descartes notices his tendency to keep falling back into his old beliefs.

  The malicious demon is a device he can use to help himself mistrust his previous beliefs and treat them as false.

  This helps him to treat seriously his speculation that the external world might be a complete illusion.
• Criticisms of Deciving God and evil demon

  Hume claimed that the evil demon argument was so powerful that it forces us to realise certain knowledge is impossible. Descartes building project is doomed.

  This would be supported by noticing another criticism of Descartes - that he later uses language, logic and other assumptions to build on the cogito. Each of these, claims the critic, should be doubted as they could be corrupted by a malicious demon.
• Sense argument


  Descartes notices that many of his strongly held beliefs are based on sense experiences. Descartes states that in the past his senses have deceived him.

  And so it would be wise not to trust the senses completely.

  Descartes give the examples of things that are far away or very small.
• Criticism of sense argument

  Descartes is right that our senses cause us to err but some argue this should not lead to a wholesale rejection. We often find out we made a mistake using our senses.
• Dream argument


  Descartes' point that the senses initially seem to be reliable for things that are very obvious, such as the fact that he is sitting by the fire holding a piece of paper in his hands his belief that he sometimes thinks he is sitting by the fire when in fact he is in bed, dreaming that he is awake.

  In dreams, Descartes says, we can have the experience of seeing things yet these things are not there in reality.

  Perhaps, then, all his supposed experiences of the external world are, similarly, a product of his mind.

  Descartes claims there are no definitive signs by which he can distinguish wakefulness from sleep.

  His conclusion is that this undermines any sense experience as he cannot be certain he is perceiving objects that are actually there.
• Criticism of dream argument

  Some people think the real world has an order that is not present in dreams.

  Even if we are unable to tell we are dreaming, it does not follow from this that we cannot tell when we are awake.
• Cogito


  In Meditation 2 Descartes, as he now knows nothing for sure, considers that he may not even exist.

  But an evil demon could not fool nothing into believing that it existed.

  And if he is doubting that he exists, then he is thinking (because doubting is a sort of thinking).

  Descartes realises that because he is thinking he must exit. I think, therefore I am.
• Criticism of Cogito


  The Cogito shows that there is a thought, not necessarily that there is a thinker.

  Some claim there is an unjustified jump in reasoning from 'I think' to 'I am'. A hidden premise (eg. 'thinking things exist') needs to be inserted to allow the conclusion.

  Accusation of circularity - the cogito is circular since it assumes what it is setting out to prove.

  Others claim Descartes does not doubt reason in his Cogito argument, despite his doubt in the Evil Genius argument about the laws of logic.
• A priori


  'Before'. Knowledge gained from reason rather than experience.
• A posteriori


  'After'. Knowledge gained from experience.
• Knowing how

  The first of these is related to abilities we have. Skills.
• Knowing that

  propositional knowledge. Facts
• What is the tripartite theory of knowledge?

  Plato argued that for something to be knowledge, three criteria must be met: you have to believe x, have sufficient reason for believing x is true and, finally, be correct that x is true. This is known as the tripartite theory of knowledge.

  Justified, True, Belief
• What are the conditions for the tripartite theory

  Individually necessary and jointly sufficient.
• Scepticism


  The belief that knowledge (either in one area or more generally) is unattainable
• Infinite regress of justification

  .

  Whenever we seek to justify or give reasons for a piece of knowledge, we realise that any justification will rely upon another knowledge claim. This then leads us to seek a further justification and so on...
• Ways to respond to the infinite regress

  1. There is an infinitely long chain of justification.

  2. There is a circular chain of justification.

  3. The chain stops with unjustified first

  knowledge.

  4. The chain stops with a self-justifying

  foundation.
• Innate idea


  Knowledge that we are thought to be born with. As such it is thought to be shared by all human beings.
• Empiricism


  The belief that all knowledge of the world ultimately depends on experience
• Locke


  An English empiricist who claimed that there were no innate ideas because there are no ideas that everyone shares.
• Blank slate metaphor


  A metaphor described by John Locke to describe how the mind gains knowledge. The slate represents the mind, and the writing represents knowledge. The process of writing represents learning through experience. The point of the metaphor is that when we are born we know nothing and all knowledge comes through the senses.
• Rationalism


  The belief that at least some knowledge of the world can be gained through reason and/or innate ideas.
• Liebniz


  A German rationalist who thought that the basic rules of logic were innate ideas. For example the idea that something cannot exist and not exist at the same time.
• Block of marble metaphor

  A metaphor described by Leibniz to describe how the mind gains knowledge. The veins in the block of marble represent innate ideas, and the finished statue represents knowledge. The process of sculpting represents experiencing the world. The point of the metaphor is that and acquire some gradually through experience. Leibniz thinks play a role in the processing of sense perceptions - they shape our knowledge.
• Standard form


  A formal way of presenting the argument which makes clear which statements are premises, how many premises there are and which statement is the conclusion. In standard form each premise takes a new line and the conclusion of the argument is listed last. The premises and conclusion are separated by a line called 'the inference bar'.
• How do you put an argument into standard form?

  1. Score out non-statements.

  2. Locate the conclusion.

  3. Which statements are premises (give evidence for

  'C')?

  4. Write out the 'cleaned up' premises in a numbered

  list. Add the conclusion as the final point.

  5. Draw an inference bar.
• False dilemma


  A conclusion is established on the grounds that it is the best of the two options presented in the argument, when in fact more than two options are available.
• Slippery slope


  A conclusion (that an initial first step should not be taken) is established on the grounds that the first step will inevitably lead to further events and/or actions and/or commitments that are undesirable, without providing good reasons to suppose that further events will follow.
• Illegitimate appeal to authority

  A conclusion is established on the grounds of a claim made by an authority when that authority is not established as authoritative on facts relevant to the argument.
• Attacking the person


  A conclusion is established on the grounds that an irrelevant personal characteristic is used as justification for rejecting what someone claims in an argument.
• Argument


  A collection of statements (the premises) put forward support a central claim (the conclusion)
• Statement


  A sentence capable of being true or false. Statements are also known as propositions.
• Non statements


  Expressions of emotion, imperatives (commands) and questions are not statements (they do not have a truth value).
• Premise


  The part of an argument which is intended to defend the conclusion.
• Conclusion


  What an argument attempts to prove the truth of.
• Valid/Invalid


  A valid argument is one which would guarantee a true conclusion if the premises were true. An invalid argument does not guarantee a true conclusion when the premises are true.
• Formal fallacy


  An error in reasoning that is fallacious by virtue of having an invalid structure or form.