Richard L. Epstein
We reason as a means to many ends. One of those is to arrive at truths. This we do with arguments. Here we’ll see what an argument is, set out criteria for what counts as a good argument, and then look at how to evaluate those conditions.
The notion of a fallacy can be a useful tool in analyzing arguments. But the usual definitions are at best unclear and not helpful. Setting out a general approach to argument analysis will lead us to a definition of “fallacy” that gives guidance for when to classify a mistake in reasoning as a fallacy and how to use that notion in argument analysis.
Induction and Deduction
No current definitions of the words “induction” and “deduction” divide arguments according to what we think those words should mean and how we want to use them. Those terms are poor substitutes for a theory of how to evaluate arguments, useful only as a marker for whether we should judge an argument as valid/invalid or on the scale from strong to weak.
Unless we accept some claims without reasoning to them, we can have no good reason to believe any claim. In this paper we’ll consider what counts as good reason to believe a claim without reasoning.
An analogy elevates a comparison into an argument, reasoning from similarities to similar conclusions. Some examples will show that analogies are often incomplete arguments. A general method is suggested for how to evaluate and repair analogies.
Subjective Claims (with Fred Kroon and William S. Robinson)
We reason about the world around us. We reason about our thoughts and feelings and the thoughts and feelings of others. We need to have a basis for distinguishing claims about these apparently different subjects in order to investigate how we do or should reason with them. After surveying ways to characterize those, we’ll propose a definition of “subjective claim” and look at examples of classifying according to it. Then we’ll turn to what role this division plays in our reasoning and what consequences that has on whether we can provide a bridge through reasoning between the mental and the nonmental in our lives.
To generalize is to make an argument from premises about a part to a conclusion about the whole. How do we evaluate such arguments? After defining what we mean by a generalization, we’ll look at the standard method for evaluating generalizations, which we’ll refine through a series of examples. Then we’ll turn to the question of whether a generalization can be a good argument.
The usual notions of probability can sometimes be useful in inference analysis, but they are not adequate to make precise the notions of plausibility or the likelihood of a possibility.
Except for a minimal notion, the use of the term "rationality" is too vague to be helpful and can be replaced with other common terms that are clearer. Generally, the ascription of rationality or irrationality is a value judgment rather than a tool of analysis.