The Critical Thinking Toolkit

Galen A. Foresman, Peter S. Fosl, Jamie C. Watson

• Publisher: Wiley-Blackwell
• Year: 2016
• ISBN:
  9781118981993
• Edition: 1
• Topic: Philosophy
• Subtopic: Logic in Philosophy

The Critical Thinking Toolkit is a comprehensive compendium that equips readers with the essential knowledge and methods for clear, analytical, logical thinking and critique in a range of scholarly contexts and everyday situations.

• Takes an expansive approach to critical thinking by exploring concepts from other disciplines, including evidence and justification from philosophy, cognitive biases and errors from psychology, race and gender from sociology and political science, and tropes and symbols from rhetoric
• Follows the proven format of The Philosopher's Toolkit and The Ethics Toolkit with concise, easily digestible entries, "see also" recommendations that connect topics, and recommended reading lists
• Allows readers to apply new critical thinking and reasoning skills with exercises and real life examples at the end of each chapter
• Written in an accessible way, it leads readers through terrain too often cluttered with jargon
• Ideal for beginning to advanced students, as well as general readers, looking for a sophisticated yet accessible introduction to critical thinking

1
Basic Tools for Critical Thinking about Arguments

1.1 Claims

“Listen to reason!” cried Charlotte, exasperated after an hour of argument with Charles. And Charlotte's frustration may have been perfectly justified. What is reason? And why should we listen to it? Most basically, reasoning is about advancing truth claims by means of special logical procedures of argument (see 1.2). One of the most basic elements of critical thinking, then, especially when engaged with issues related to logic and science, is to discern whether claims are actually true and to distinguish them from claims that are not true.

In practice, language is our most fundamental tool in this process. Language allows us to articulate what we judge to be true or false, and it allows us to share and communicate those judgments to others. Ultimately, a good critical thinker must develop an acute grasp of language in order to make clear and precise claims about the truth and to assess how well or badly they function in the logic of an argument. Logicians have technical names for the kind of sentences out of which logical arguments are built. They call them statements or propositions, and they're simply sentences that can be either true or false (in logical terms, they possess a truth value). To really understand statements and their truth values, however, keep the following in mind.

• Bivalence. Statements or propositions can only have one truth value, and it must only be either true or false. Moreover, statements or propositions can't be both true and false in the same sense under the same circumstances. Logicians call this the principle the law of bivalence. (To be sure, there are multi-valued logics with values besides true and false, but again they're the subject of a different, more advanced book.)
• Excluded middle. There's no middle ground or gray area between truth values in basic logic – no “truthiness” as the comedian Steven Colbert might say. Statements or propositions can't be “sort of true” and “sort of false.” Logicians call this requirement the law of excluded middle. (Yep, there are fuzzy logics that accept gray areas, but we won't be dealing with them here.)
• Non-statements and propositions. Keep in mind, too, that sentences that aren't (in logic's technical sense) statements or propositions simply don't have truth value. Neither questions (“Where are you going?”) nor commands (“Stop that!”) nor exclamations (“Wow!!!”) are properly speaking true or false; and so they can't be proper parts of arguments, logically understood.

Now, the idea of a claim, in the sense we use the term here, adds for the sake of critical thinking just a bit more to what logicians strictly call statements and propositions. In particular, claims are statements that indicate a position has been taken. A claim, in other words, is a statement or proposition that in some meaningful sense sincerely belongs to whomever or whatever asserts it. One of the first judgments a good critical thinker must make, then, is to determine in just what way a statement is presented. Perhaps it's meant sincerely and seriously, but perhaps it's just being used hypothetically, ironically, as a joke, an instructive example, a lie, or perhaps in the recitation of some movie script. Or maybe it is simply being used to provoke an audience, to gain attention, to test someone's response, or perhaps for some other reason entirely. There are countless things one can do with words and other forms of expression. So, while most of the material in this and the next four chapters applies to all claims, and not just to statements or propositions, we will use the language of “claims” to keep the question of claim or non-claim in mind.

Here's the upshot. Since it's often the case that critical thinking involves discerning truth and error, a good critical thinker must learn how to identify claims that are true, or most likely seem true, while at the same time recognizing and avoiding claims that are best judged false. What's more, a good critical thinker will recognize and admit when he or she does not know whether a claim is true or false. Critical thinking sometimes requires reserving judgment as to whether or not a claim is true until, if ever, sufficient reason for determining the truth or falsity of that claim is discovered.

Beliefs and opinions

In the 1989 comedy film, The Big Lebowski, a competitor scheduled to face the main character, the Dude, in the next round of a bowling tournament declares that his team is going to crush the Dude's. The Dude, at least pretending to be unfazed, responds, now famously, by remarking, “Well, that's just your opinion, man.” It's not uncommon for people to distinguish strong truth claims from those that are weaker by calling the weaker claims opinions. People often make claims such as, “The world is round,” implying it's something we definitely know to be true, that it's a fact. When, on the other hand, people make claims such as, “Pele was a better athlete than Gretzky,” we deflate the claim by saying that it's just their “opinion.”

Beliefs can obviously often be either true or false, but a misleading though nevertheless common misunderstanding about the difference between strong assertions (such as knowledge claims) and mere opinions is that opinions aren't really true or false. As such, they're often thought to be free from the same scrutiny and justification required by claims to know. The result of this mistaken view is that many people believe that one's opinions are somehow insulated from dispute or challenge. Opinions are treated as if they stand alone as islands in our thoughts, entirely disconnected from criticism and critical thinking. In reality, however, our opinions are still very much claims open to criticism. They are, after all, claims, and therefore either true or false. (Matters concerned with knowing are described as epistemic, and epistemology is the study of knowledge. Matters concerned with belief we'll sometimes call doxastic.)

In addition, it's important to understand that opinions are often influenced by what we value. This mixing of beliefs and values sometimes makes it difficult or confusing to assess their truth. But a good critical thinker's toolkit provides the tools for tackling this seemingly tricky task (see 5.5, 7.2, 8.2, and 8.5). In the meantime, just keep in mind that opinions often incorporate judgments and emotions about what is valuable, either subjectively, to the person expressing the opinion, or objectively, to everyone in the world.

Simple and complex claims

A simple claim is a claim that, logically speaking, isn't divisible into other, more basic claims. This is usually a single subject-predicate formula, for example, “It is a cat,” or “That ball is round.” A complex or compound claim is a claim logically composed of two or more claims (or, minimally, a single claim that's negated) connected by special words or ideas logicians c...