Logic - Chapter 3b - Salmon

(Originally written September 9, 2005 in Book 1)

Logic
Wesley C. Salmon
Chapter 3

Analogy:

Analogy is a widely used form of inductive argument based upon a comparison between objects of two different types. The form is:

Objects of type X have properties G & H
Objects of type Y have properties of G & H
Objects of type X have property F
Therefore, objects of type Y have property F.

An analogies strength (or weakness) is based upon the similarities of the objects being compared. The similarities or dissimilarities of two objects can be both numerous, but for an analogy to be strengthened or weakened the similarities/dissimilarities are focused on the relevancy of the argument.

The Design argument (most widely used for the existence of God)

Causal Arguments and Causal Fallacies:

Argument occurs when a statement is made after an observation with the help of personal knowledge. For example: A ranger observing lightning striking a dry forest and he infers that a fire will ensue. It is a cause to effect on the basis of a knowledge of causal relations.

Superstition causes many fallacies and incorrect premises in correct inductive arguments.

Post hoc ergo propter hoc is a causal fallacy. It is the fallacy of assuming that since B followed A, B was caused by A.

The fallacy of confusing cause and effect is when the cause and the effect are switched.

The fallacy of the common cause is when the two events are causally related but not in the cause-effect relationship. Both events could be effects of another cause.

A hypothesis is a statement that is taken as a premise, in that its logical consequences can be examined and compared with facts that can ascertained by observation. A hypothesis is confirmed if it is adequately supported by inductive evidence. Then the conclusion strengthens the hypothesis in most cases.

The Hypothetic-Deductive Method is:
1) Setting up a hypothesis
2) Deducing consequences from the hypothesis
3) Checking by observation to see whether these consequences are true.

The form is:

Hypothesis.
Therefore, Deduced consequences.

Auxiliary hypotheses are hypotheses that have been confirmed previously and are used to conclude the observational predication (deduce consequences)