Inductive Arguments

Classes of Argumentation:Induction

Inductive Methods

Antecedent Probability

Induction is the process of reasoning whereby from the concurrence or conjunction of particular instances or phenomena we draw a general principle, rule o postulate.In Induction, the mind starts from particular phenomena, facts or instances; and from their conjunction or concurrence it infers a general truth.

Standard Usage of Inductive Argument in Logic

5 Inductive Methods

“If two or more instances of a phenomenon under investigation have only one instances in common , the circumstances in which one alone all the instances agree is the cause of the given phenomenon.”

The Method of agreement

Method of agreement

Example: Some cities have markedly lower rates of tooth decay.

- Is there anything else these cities share in common?

• If so, that is the likely cause of lower ratesof tooth decay.

Four patients all show amnesia after brain injury:

- Patient 1--damage to the prefrontal cortex and the hippocampus-Patient 2--damage to the hippocampus and amygdala-Patient 3--damage to the thalamus and hippocampus- Patient 4--damage to the hypothalamus and hippocampus

The Method of difference

“If an instance in which the phenomenon under investigation occurs, and instance in which it does not occur, have every circumstance in common save one, that one occurring only in the former; the circumstance in which alone the two circumstances differ, is the effect, or the cause or an indispensable part of the cause, of the phenomenon.”

Example:

A B C D occur together with w x y z.B C D occur together with x y z.

Therefore, A is the cause or the effect or an indispensable part of the cause of W.

The Joint method of agreement and difference

“If two or more instances, in which the phenomenon occurs, have only one circumstance in common, while two or more instances in which it does not occur have nothing in common save the absence of the circumstance; the circumstance in which alone the two sets differ is the effect, or the cause, or an indispensable part of the cause of the phenomenon.”

Example:

Five factory workers are found to be inefficient relative to others who are doing the same work.

The efficient workers and the inefficient workers werefound to be similar in all relevant ways except one: theinefficient workers were not part of a profit sharing plan.

Conclusion: profit sharing causes efficiency.

The Method of residues

“Sub duct from any phenomenon such part is known by previous inductions to be the effect of certain antecedents, and the residue of the phenomenon is the effect of the remaining antecedents.”

Example:

A B C ----- x y zB is known to be the cause of yC is known to be the cause of z

Therefore, A is the cause of x

The Method of concomitant variations

“Whatever phenomenon varies in any manner when ever another phenomenon varies in some particular manner is either a cause or an effect of the phenomenon or connected with it’s through come fact of causation.”

A B C ---- X Y ZA + B C ---- X + Y Z

Therefore, A is always connected with X

Eating one fish meal a week reduced the risk of heart attack by 50%,Eating just two fish a month reduced the risk of heart attack by 30%

Therefore, eating fish can reduce the risk of heart attack.

What is Mill saying?Mill’s methods are useful in clarifying ourunderstanding of cause and how we test for it.one and only one factor is the cause, and it is one you have considered.

Argument from Antecedent Probability

Antecedent Probability

Is an inference from a known cause to an unknown effect. This type of argument is also called an priori argument.

This is an argument from cause to effect.

To bring another fact.

Reference:

http//www.Science and Mill's Methods of Induction by Roberto Ruiz on Prezi.com

Phil12_W10_Mill's_methods(2-22-2010).pdf

http://en.wikipedia.org/w/index.php?title=Inductive_reasoning&oldid=559982096

Deductive and Inductive Arguments", Internet Encyclopedia