workbook on critical thinking - Gary Jason

A Brief Manual on Critical Thinking copyright 1991 by Gary Jason
CONTENTS Chapter Page
1. Introduction 3
2. The Concept of an Argument 4
3. Identifying Single Arguments 7
4. Critical Reading 9
5. Figuring Out Your Own Point of View 10
6. Tips on Writing 12
7. How NOT to Argue 14
1. Introduction In this manual I want to develop your skills in "critical thinking."
By that phrase I mean simply the ability to read (or listen to) someone's
ideas, put them in logical order, formulate your own position on the issue
at hand, and finally set forth your own ideas forcefully and cogently.
This sort of activity--broadly called "reasoning"--is something that
requires training and practice. This is news to some people who seem to
feel that we are all born knowing how to reason well. Alas, not so!
Indeed, the main reason why students are forced to take "general ed"
classes is to train them in the skills of reading and writing.
We ought to begin by asking, what is reasoning? It is clearly a
common activity. But it is certainly a curious sort of thing, being part
social and part solitary. It is something we usually need others to
initiate and help us with, but yet is something we use our heads to do.
For a moment, let's focus on the social aspect of reasoning, an
activity that is as common as playing. When we sit in a coffee-shop
discussing the movie we just saw, perhaps, or the break-up of a friendship,
or who to vote for in the next election, we expect each other to reason:
you don't just say the movie was trash; you try (somehow) to defend your
claim. That's reasoning. Indeed, our language has built into it two types
of words, one type used to signal others that we don't want to engage in
reasoning, the other used when we do. Compare these sentences: 1a) I like cheese. 1b) Cheese is good.
2a) I didn't enjoy the movie 2b) The movie was not
well written.
3a) I dislike Fred. 3b) Fred is evil.
4a) I guess the business will do well. 4b) I urge you to buy
stock in that business.
5a) I hope John wins. 5b) John will win. Note that the ones on the right seem stronger, in that they set up the
expectation that reasons for the claim will be soon forthcoming. If
someone makes a b-type claim, then refuses to argue for it but only
substitutes an a-type claim, we feel he has done something socially
unacceptable, he has not done what he implicitly promised to do.
Of course, reasoning as a social activity can range from the very
informal (in the sense of being not socially structured) to the very
ritualized, not to say stereotypic. Chatting about sports, say, is done in
a very unstructured way. But the reasoning involved in solving a
scientific problem or settling a case at law is constrained by a large
number of written and unwritten rules.
Shifting to the solitary aspect of reasoning, we use our brains to
think through issues, to figure out reasons to back up our statements, and
so on. How this happens is a fascinating question I leave to the cognitive
psychologists. What we are interested in in this course are the "products"
of that mental process, things we call "arguments." Roughly defined, an
argument is just some claim, together with the "reasons" for it. By
"reasons" I don't mean to imply "good reasons;" in fact, the reasons put
forward may be utterly stupid ones. We want to distinguish good reasons
from bad.
2. The Concept of an Argument We need to get more precise about the concept of an argument. Let me
begin by defining a statement as any assertion or claim that something is
the case.
Statements are the kinds of things that can be true or false.
Indeed, we shall adopt the dogma that each statement is either true
(hereafter abbreviated "T") or false ("F"), not both and at least one.
In saying statements are the kinds of things that can be T or F, I
mean to distinguish them from questions and commands. It makes no sense to
answer to question "What time is it?" by "I disagree--you're absolutely
wrong." Saying the question is wrong (or correct) is strange; questions
can be loaded, stupid, based on mistaken assumptions or misleading--but
never T or F. Similarly, it makes no sense to speak of a command as being
T or F; you can't very well reply to the order "Go shoot that man!" by
saying "Sir, your order is false." Orders can be called immoral,
inappropriate or stupid, and can be disobeyed--but they aren't T or F.
It is easy to confound statements with sentences, especially
declarative sentences of English. But you shouldn't confound them. After
all, the same declarative sentence may be used to make different statements
in different contexts. For example, "I am hungry," a rather short sentence
of English, can be used to make billions of statements--because it can be
uttered by billions of people. (The statements thus made would be T or F,
depending on whether the person uttering it was in fact hungry.)
Moreover, different English declaratives may be used to make the same
claim (statement). For example, the active and passive voice constructions
"John loves Mary" and "Mary is loved by John" are used to say the same
thing. But they are clearly different sentences (i.e., they are different
grammatical strings of words): the first has only three words, the second
has five.
Of more philosophic interest is this. We often make statements using
non-declarative sentences. You know of "rhetorical questions," which are
interrogative sentences (like "Do you really like that?") used to state
claims (here, that the listener is mistaken). But there are rhetorical
commands as well. "Stick it in your ear!" and "Take a walk!" likewise
typically express the statement that the listener is wrong, even though a
non-declarative sentence (here, an imperative) is used.
To further emphasize the fact that statements aren't sentences,
remember that until now we have been dealing solely with English. It
should be clear that sentences from different natural languages can be used
to make the same claim: "John is rich" and "Juan es rico," for example.
Somewhat less obvious is the fact that gestures and noises can express
statements as well. A Bronx cheer can be used to deny (emphatically,
albeit crudely) another's assertion; so can an obscene gesture.
These remarks should give you an idea of what a statement is. An
argument, then, is just a set of one or more statements, called "premises,"
considered by us (the logical observers) to be possible evidence for
another statement, called "the conclusion." Arguments are just fancy sets
of statements. We (the assessors) view them as representing a process of
mental inference in someone's head--starting with those premises and ending
up with the conclusion. But that is sheer psychological conjecture on our
parts. The argument is considered entirely on its own, in total
abstraction from the context in which it arose (if it was ever given at
all).
An argument as we define the term has at least one and at most
finitely many premises. There are one-premise arguments: 1. Men are greedy.
/ ( Any social system that requires altruism is doomed to
failure. Here, the symbol "(" abbreviates "therefore."
There are two-premise arguments: 1. One should only negotiate from a position of strength.
2. America is weaker than Russia.
/ ( America should not negotiate with Russia. There are three-, four-, five-, even hundred-premise arguments. Consider: 1. Unemployment is high.
2. Inflation still rages.
3. Our enemies are challenging us constantly.
4. Our relations with our allies have deteriorated.
5. The energy crisis gets worse and worse.
/(The President is doing a bad job. Please note that by itself a statement is neither a premise nor a
conclusion, any more than a person is by himself a brother or a cousin.
Being a premise, like being a cousin, is being related in a certain way to
something else. The same statement may be a premise in one argument and a
conclusion in another. Thus "Dogs make good pets" is a conclusion in: 1. Dogs are affectionate.
2. Dogs are protective.
3. Dogs are fun to be with.
/(Dogs make good pets. Yet the same statement is a premise in: 1. Dogs make good pets.
2. We want a good pet.
/(We should buy a dog. Put another way, the main feature of an argument is not so much what
makes it up (statement), but how they are structured. So: Argument I:
Argument II:
1) Sue will date Fred. 1) Sue is a real gambler.
/(Sue is a real gambler. /(Sue will date
Fred. are quite different arguments (silly as they are). In the first, I take it
as clearly true that Sue is going to date Fred, and I am using that to
prove what I think is less clear (that she must be some kind of chance-
taker). It is the reverse in the second argument. By the way, we have displayed all our sample arguments with the
premises on top of a line, and the conclusion underneath. This is termed
"putting the argument in standard form," and we shall learn how to put