Notes on Induction, Hypothesis Testing, Inference, and Argument Analysis

Induction is a type of reasoning where past observed cases are used to infer that the same event or property will occur in unobserved cases.
Example: Because paper has always burned when placed in a flame, we infer it will burn in the present case.
The strength of belief in a claim should vary with the amount of evidence supporting it; more positive instances should increase the strength of belief.
A negative instance can immediately disprove a generalization, while positive instances gradually confirm it.
Varied evidence is a condition for good inductive reasoning. Observing buses in different parts of town strengthens the claim that all buses in town are green.

Hypothesis testing involves creating hypotheses and accepting those that pass tests. This process is similar to inductive reasoning.
Example: Residents are falling sick, complaining of severe nausea, abdominal pain, and other c symptom symptoms. The local doctor hypothesized that the trouble has been caused by the opening of a new chemical plant that is emptying waste within a mile of one of the lakes that yield the town's supply of drinking water.
Hypotheses are tested by considering expected observations if the hypothesis is true and then investigating whether these expectations are met.
If the expectations are confirmed, the hypothesis is supported; if not, the hypothesis is weakened.

Inference to the best explanation involves inferring a conclusion based on the fact that the claims made by the conclusion would explain all the facts presented.
Example (Sherlock Holmes): Holmes infers that Watson has been in Afghanistan based on his military bearing, medical bag, tan, and wounded arm.
The conclusion provides the best explanation for the observed facts.

Argument analysis involves providing a clear formulation of the argumentation.
The initial step is to find the conclusion by asking, "What is the author trying to get us to believe?"
The next step is to list the stated premises, identifying what claims the author assumes without argument.
Then, trace a possible route from the premises to the conclusion, adding unstated assumptions and clarifying key terms.
Finally, appraise the argument's success or failure using criteria for evaluating different types of inferences.

Effective reasoning calls for avoiding fallacious arguments and clarifying ambiguous terms.
Some commonly used words are so notoriously vague that their appearance in any argument signals trouble.