Philosophy – key words

By the end of this lesson you will have:

Understand the principles of philosophical proof for

the existence of God.Understand the following

essential terminology:A-priori, a-posteriori,

analytic, synthetic, inductive, deductive

Philosophical Proof

• Premise: a statement upon which an argument is based from which a conclusion is drawn.

ProofProof from premisesDirect proof

Olivia has broken her leg can be proved by

an x-ray.

Pythagoras’ theorem.

Philosophical Proof

• Philosophers tend to use premises for their arguments

• Why?• The philosopher wants the atheist to be able to

follow his line of argument. Therefore he starts with unexceptional statements that everyone would agree with and then tries to convince a reasonable person that belief is necessary.

Proof from Premises

• Example• P: The world is beautiful.• C: God must have made such a beautiful

world.

Direct Proof

• The arguments could be direct proof, for example someone has a vision.

• However, this is less convincing for some.

Specialist Vocabulary

• Analytic statement:• A statement true by definition. • E.g: Frozen water is ice

• Synthetic statement:• A statement in which its truth or falsity depends on

evidence that has to be collected. • E.g: My computer is on.

• TASK: Card sort – which statements are analytic and which are synthetic?

Specialist Vocabulary

• A priori knowledge• Knowledge that is gained from logical reasoning

without or prior to experience.

• A posteriori knowledge:• Knowledge that is gained after (post) experience.

• TASK: Card sort – which statements are analytic and which are synthetic?

What have you noticed?

• Analytic + a-priori• Synthetic + a-posteriori

Inductive Arguments

• An argument in which the premises only support the conclusion, making the conclusion likely, but not definate

Inductive Arguments

• P1: The sun rose today• P2: The sun rose yesterday• C: The sun will rise tomorrow.

Comments:

Inductive Arguments

• P1: Huw is Welsh• P2: Huw is a good singer• C: All Welsh men sing well.

• Comments:

Inductive Arguments

• In inductive arguments, you can accept all the evidence, but still deny the conclusion, without contradicting yourself.

• For example, in a crime all evidence might point to a suspect. He is most likely to be guilty. However, even if all the evidence is correct, there is still the possibility that he is innocent.

• Fugitive clip

Inductive Arguments

• Monty Python.• http://www.youtube.com/watch?v=zrzMhU_4

m-g

Inductive Arguments

• Which of the following words can be attributed to inductive arguments? And why?

• Analytic• Synthetic• A-priori• A-posteriori

Deductive Arguments

• An argument in which if you agree with the premises you have to accept the conclusion to be true.

Deductive Arguments

• P1: All queens of England are female• P2: Queen Elizabeth I was a queen of England• C: Queen Elizabeth I was female.

Deductive Arguments• P1: All men are mortal.• P2: Einstein was a man.• C: Einstein was mortal.• If you agree with the premises, the conclusion has to

be true (otherwise you would contradict yourself). • The conclusion follows logically, of necessity. • Note: The premise may not be ‘true’ but the form of

the argument is nevertheless ‘valid’.

Deductive Arguments

• Which of the following words can be attributed to deductive arguments?

• Analytic• Synthetic• A-priori• A-posteriori

Strengths and Weaknesses

• Complete the table by copying the sentences into the correct place.

• Check your answers ...

Inductive Arguments

Strengths• They rely on experience

that may be universal, or at least may be testable.

• They are flexible, there is more than one possible conclusion.

• They do not demand that we accept definitions as fixed.

Weaknesses• They rely on accepting

the nature of the evidence.

• They demand overwhelmingly good reasons for accepting that the conclusion is most likely.

• Alternative conclusions may be just as convincing.

Deductive Arguments

Strengths• They do not depend on

variable or misunderstood experience.

• It accepts that words and definitions have fixed and agreed meanings.

• There are no alternative conclusions.

Weaknesses• They lead to apparently

logically necessary conclusions.

• They depend on whether we accept the premises as analytically true.

• They can only say that if there is a God we might be able to make certain claims about him.

Homework - Revise

• Analytic• Synthetic• A-priori• A-posteriori• Inductive• Deductive

Learn the key vocabulary from today’s lesson. You will have a short test next lesson.

Philosophy – key words

By the end of this lesson you will have:

Understand the principles of philosophical proof for

the existence of God.Understand the following

essential terminology:A-priori, a-posteriori,

analytic, synthetic, inductive, deductive