Lecture Notes by Christopher Lay
Los Angeles Pierce College
Department of History, Philosophy, and Sociology
Mathew Van Cleave's 2016 Introduction to Logic and Critical Thinking
https://open.umn.edu/opentextbooks/BookDetail.aspx?bookId=457
Chapter 4 "Informal fallacies", § 1 "Formal vs. Informal Fallacies"
"A fallacy is simply a mistake in reasoning."
"Some fallacies are formal and some are informal."
(Note that the introduction to this chapter makes references to parts of the text we haven't covered, e.g. formal logic which is needed to understand formal fallacies. We'll cover those parts later.)
From the next sub-§: With "an informal fallacy ... we have to rely on our understanding of the meanings of the words or concepts involved ... ."
With formal fallacies (as we'll see later in the course), we can "simply ... identify the fallacy from its form."