The Application of Reason

So let’s begin to apply reason to all of this..

• Propositional knowledge is a knowledge claim in which we state that we know something but in actual fact, an assumption is present

Identify the inferences in the propositions below:• The signing by Kim Il Sung on the 7th July 1994

of the reunification treaty will remove the final barriers for the coming together of the two nations.

• The introduction of a national health service in America will be the end of a free America.

Where language and reason (fallacies in) overlap

Failure in Classification: e.g. Dolphins – consequences of false classification

Dichotomy – where the second class is defined simply by its absence of something

The Jewish Doctor in N. Ireland

Slippery Slope Arguments-arguing that there is no distinction between where a property possesses

or doesn’t possess something

Hair Splitting- e.g. the perfect triangle

Come up with your own examples of each

Ambiguity

• Where an argument depends on the ambiguity of a word, leading to false assumptions:

• Gareth’s classes are inflammatory, since inflammatory speech should lead to the deportation of foreigners, we can expect to see Gareth gone soon.

• Since an elephant is an animal, a small elephant must be a small animal

• This is the People’s Republic of China, there must be a lot of individual freedom

problem of composition • Incorrectly applying qualities of the whole to the

individual and visa versa. Also, applying the quality of one thing, to a collection of those things.

• Every Cardiff City player is of low quality, therefore the team must be no good.

• The Chinese army is extremely powerful therefore this soldier is a threat to our nation.

• A car uses less petrol than a bus, so it will cause less pollution than a bus. Therefore cars are less environmentally damaging than buses.

Problem with Definition• How do we define things?• Aristotle – Analytical Definition. First look for the

genus, then the property which distinguishes it.

plane figure

triangles quadrilaterals polygons

What are the limitations of this method?Look through a dictionary, find some words that

don’t fit neatly into Aristotle’s method.

Circular Arguments

• From Colin Powell “A Soldier’s Way”• Asked why a base had been erected in

such a vulnerable position:• “What is the mission,” he asked.• “Very important post,” came back the reply.• “But why is it here?”• “Outpost is here to protect the airfield.”• “What is the airfield here for?”• “Airfield here to supply outpost.”

InductionRussell’s Turkey – search for your own example in different areas of knowledge

“The general principle of science, such as the belief in the reign of law, and the belief that

every event must have a cause, are as completely dependent upon the inductive principle as are the beliefs of daily life.”

What type of argument is one that relies on a premise previously stated?

Aristotle on Identifying Causes

• Expect precision only to the extent the subject admits of it. We do not ask for probable reasoning from a mathematician or for certainty from a shoe carpenter. (paraphrased)

• Aristotle was interested in the teleological cause of things/ideas – what is that makes them exist or conceives of them in the first place