Critical thinking

Categories of Arguments

A key skill when evaluating information is the ability to evaluate the strength of an argument and decide whether it’s reasonable. But what do we mean when we talk about arguments? Pause for a moment to consider the following question. When you have an answer, turn the card to learn more.

Arguments can be divided into two categories:

If premises are true, then conclusions must also be true.

Example : Claire likes cats. Bella is a cat. Therefore, Claire likes Bella.

If premises are true or have a high likelihood of being true, then conclusions are likely to be true, but not guaranteed.

Example: In most cases, where there is smoke, there is fire. There is smoke on the mountain. Therefore there is probably a fire on the mountain.

Let’s explore through an example the different ways deductive and inductive arguments are constructed and analysed.

Deductive Inductive
Observation – a phenomena is observed
  • Home break ins by high school students increase towards the end of school holidays
 Observation – a phenomena is observed
  • Home break ins by high school students increase towards the end of school holidays
Theory – is developed to explain why it occurred
  • Boredom in high school students towards the end of school holidays can lead to anti-social behaviour during this time
 Data is collected to determine the possible reasons for this trend
  • Statistics of high school students who have broken into homes towards the end of school holidays are gathered to show whether this cohort are engaged in work, social or sporting activities during this time

Trends in data
  • Statistics show that the majority are not engaged in work, social or sporting activities during this time
Explanation – theory is analysed/tested and either accepted, rejected or revised
  • Statistics of high school students who have broken into homes towards the end of school holidays show whether this cohort are engaged in work, social or sporting activities during this time
 Theory
  • Boredom in high school students towards the end of school holidays can lead to anti-social behaviour during this time

Evaluating arguments

Arguments can be evaluated by following four steps:

  1. Begin by deconstructing the argument so that you can identify its premises, the assumptions that underpin in, and its conclusions.
  2. Establish whether the argument is deductive or inductive
  3. Determine whether the argument is logically valid. Does the conclusion follow from the premises? Is there any missing information or hidden premises that would be required to make the conclusion valid?
  4. If you feel that the conclusions are valid, check that the premises are true

Evaluating arguments can be difficult at first. For an example of evaluation in action, watch this video which evaluates a common argument connected to climate change produced by staff at the University of Queensland (and if you’re interested you can read their full paper examining this issue).