Reason : The final chapter

Fallacies:

Recap Fallacies:• Post hoc ergo propter hoc• Ad Hominem Fallacy• Circular reasoning• Equivocation• False Dilemma

More Fallacies!• Special pleading • Argument ad ignorantiam• False Analogy• Loaded questions

Fallacies

Special pleading• This fallacy involves the use of double

Standards.• The speaker makes an exception in

their own case, that would not be found to be acceptable if it came from someone else. Eg:

• Imagine there is a drought and a hosepipe ban.

• “I know there is a drought and we need to save water, but I am putting my prize flowers in a competition next week and I need to give them plenty of water.”

• He is giving a justification for his behaviour that he would not accept if it were given by someone else.

FallaciesRichard Dawkins

• This fallacy is committed every time a person claims something is true, on the grounds that there is no evidence to disprove it.

“There is an infinity of possible things that one might believe – unicorns

Fairies, millions of things - just because you can’t

disprove them doesn’t mean there is anything plausible about them.”

Argument ad ignorantiam

fallacies

False Analogy• In trying to persuade people

of something you might use various analogies to support your argument.

• An analogy is a comparison between one thing another which implies that the two are similar in some significant sense.

• This can be an effective rhetorical device

• A false analogy arises when you assume that because two things are similar in some respects they must also be similar in some further respect.

False Analogy

• This is William Paley.• Some people think that

Paley was guilty of a making false analogy in his Teleological argument for the existence of God.

• Lets see why:

False Analogy• Paley compared the universe to a

watch.• He said that because a watch is so

intelligently designed, we should assume the existence of a designer, or watchmaker.

• He then said that because the universe also appears to have been intelligently designed, we should infer the existence of a designer here too.

• He said this designer was God.

• Some people would argue that the comparison of a watch to the universe is a false analogy.

• This is because the two things are radically different in a number of ways, apart from the fact that they are both complicated to an extent.

fallacies

Loaded Questions• A loaded question is one that

contains a built-in assumption that has not been justified and may be false.

• For example, imagine if someone asked you the question..

• If you answer:• Then you are admitting that you

always cheat. But if you answer:

• Then you are implying that you sometimes cheat.

• What you have to do is challenge the assumption built into the question and say:

“Do you always cheat in exams?”

“Yes” “No”

“No -I never cheat in exams.”

Reason and certainty

Reason and certainty

• We have looked at inductive reason, deductive reason.

• The fact that fallacies can arise with both these kinds of reason suggests that we cannot always rely on reason to give us knowledge.

• The conclusions of deductive arguments can be no more certain than the premises they are based on.

• In practice then, it seems that at best, reason is a means of preserving truth, only in the sense that if a person starts with truth, and reasons validly, they will also end up with truth.

• However we might say that as a way of thinking, logical reasoning cannot really be doubted.

• This reasoning is based on three laws...

The three Laws of Thought

• 1) the law of identity– If A, then A.– ‘if something is an

orange, then it is an orange.’

• 2) the law of non-contradiction– Nothing can be both A

and not A– “nothing can be both an

orange and not-an-orange

• 3) the law of the excluded Middle– Everything is either A or

not A– ‘everything is either an

orange or not an orange.’

• These may seem fairly obvious and irrefutable. • if you take all the oranges in the universe and

put them on your left• And take all the non-oranges and put them on

the right• There is nothing left in the middle hovering

uncertainly between being and not being an orange

An orange with an identity crisis?

“Why should I be logical?”

What to say to a person who asks why they should be logical:

On one level this question is self-defeating , because in asking for reasons, the person has pre-supposed the value of logic.

In fact, logic is pre-supposed in all meaningful communication.

Surely any assertion that P, if it is to make sense, must exclude the proposition not P.

“ we have a love-hate relationship”

Is it possible to both ‘love’ and ‘not love’ someone?

• This is true in some ways, but not in a way that undermines logic.

• You cannot love and not love the same person in the same way at the same time.

• What you really mean when you say you are in a ‘love-hate’ relationship, is that you love them in certain ways or at certain times, and hate in certain ways or at certain times. Never both at the same time.

Cathy and Heathcliff might be said to have a love-hate relationship in Emily Bronte’s story Wuthering Heights

How rational are you?

Use your logical skills and lateral thinking to solve the following situations:

• A man walks into a bar and asks for a glass of water.

• The barman pulls out a gun and points it up at the man.

• The man says ‘thank you’ and walks out. Solution:

the man had hiccups

Lateral thinking questions

• A man is lying dead in a field

• Next to him there is an unopened package.

• There is not other living creature in the field.

• How did he get there? • Solution:The man’s parachute

failed to open.

Lateral thinking

• Anthony and Cleopatra are lying dead on the floor of a villa in Egypt.

• Nearby is a broken bowl.

• There is no mark on either of their bodies and they were not poisoned.

• How did they die?

• Solution:Anthony and Cleopatra

are goldfish

Evaluating Reason

Rene Descartes• He was a Rationalist

Philosopher • He thought that Reason as a

way of knowing could provide us with absolute certainty.

• But we have seen that this is dubious

• because reason is only as certain as the premises on which it is based.

Beware the prison of

logic

Evaluating Reason• Reason can sometimes

become a double-edged tool

• We need to reason to develop consistent beliefs about the world, but can sometimes become trapped in the so called ‘prison of logic’.

• Reason is not appropriate to be used in every situation;

• And if someone is too rational they may simply come across as cold and unfeeling.

• In private life, for example the best way to resolve a dispute with a loved-one may not be by proving their inconsistency to them,

• But by showing them empathy, compassion and understanding.

Essay Question:

All knowledge claims should be open to rational criticism. On what grounds and to what extent would you agree with this assertion?

All knowledge claims should be open to rational criticism. On what grounds and to what extent would you agree with this assertion?

Things to consider when writing the essay:

• Is there any kind of knowledge which is great enough to override reason?

• If so, what is it? when might it occur? and how do we know that it is genuine?

• If not, then how do we know reason is the most reliable form of knowledge?