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Errors in argumentation: bias and poor reasoning

When we engage with arguments, we sometimes take shortcuts that can undermine our critical thinking.

One shortcut to be cautious of is using the same reasoning for arguments that look similar. If an argument looks very much like another one you have just evaluated, it is tempting to save time by using the same approach again.
Another potentially misleading shortcut is relying on intuition or feelings. If you agree with something, you probably “feel” it is a good argument. Likewise if you disagree, you probably “feel” the argument is flawed or incorrect.

Shortcuts in thinking and feeling can speed up your analysis and evaluation, but also undermine your critical thinking. You can miss errors in reasoning, weak evidence or unsubstantiated assumptions.

Such shortcuts can easily turn into bias and poor reasoning. Both biases and poor reasoning are errors in thinking and argumentation.

Note

Because bias and poor reasoning can look like “feel good” shortcuts, it is essential that you recognise them. They are often used to create cohesion in social groups, but also to confuse or spread misinformation. For example, members of group A can share an unsubstantiated argument that they are better than group B, to make group A members feel good about being part of such a group. Another example is misinformation, which can be widely spread on the internet because it “feels good” and seems like a good argument, although its reasoning is flawed.

What is a bias and how to evaluate it?

Biases are perceptions and judgements made by the human mind, and can often be the basis for errors in our reasoning. They can be based on sex, race, gender, age, beliefs or politics, and can impact how the information is gathered or judgements are made.

Recognising bias will help you evaluate the motives of the person who created the argument. In many instances they may not be aware of their biases. However, if they have a specific agenda they may be deliberately constructing their argument from a biased position. Once you are aware of any biases in an argument you are more likely to identify arguments, claims and evidence that have been misrepresented or ignored.

Here are some examples:

This is the tendency to look for information, evidence and opinions that confirm pre-existing beliefs.
When evaluating an argument ask yourself:
- Is this argument based on good evidence and reasoning?
- Are the claims based on all sides of the argument or, are they based only on a particular side?
- Is the counterargument, which might refute the argument, excluded or ignored?
This is the tendency to believe what other people think, or do what they do, just because other people are thinking or doing it. Sometimes it is called the “bandwagon” bias or fallacy.
When evaluating an argument ask yourself:
- Is the argument relying on consensus as a source of evidence?
- Does the argument provide reasons for the consensus?
- Is the argument suggesting your view is not valid or is inferior if you don’t agree with the consensus without providing reasons and credible evidence?
This is the tendency to believe a cost of time, money or energy will go to waste if a new course of action is taken.
When evaluating an argument ask yourself:
- Does the argument justify future actions based on resources used in the past actions and ignore the fact that continuing in the same way may result in a worse outcome?
- Does the argument object to a course of action claiming that changing the course of action is wasted time, money or energy?

What is poor reasoning and how to evaluate it?

Arguments, claims, reasons and evidence are held together by logic. The evaluation of an argument’s logical structure ensures that it is not based on flawed patterns of reasoning. Flawed patterns of reasoning, commonly known as logical fallacies, indicate a weak or invalid argument.

Understanding common logical fallacies can help you identify weak arguments, as well as improve your own argumentation skills. The following are some examples of fallacies and an explanation as to why they represent poor reasoning.

Attacking the person is sometimes referred to as the ‘Ad hominem fallacy’ (ad hominem means “towards the person” in Latin). This is a reasoning flaw, because it relies on insulting or discrediting the person making the argument rather than on providing reasons or objections against the argument being made.
When evaluating an argument ask yourself:
- Are the evidence, reasons and objections used to oppose the original argument based only on a judgment of personal characteristics or flaws of the author?
- Is the counter-argument opposing the original argument by providing relevant evidence and reasoning or is it attacking the author without engaging with the argument, reasoning or evidence?
This form of reasoning flaw claims that a series of events will occur as a result of an initial argument or course of action and that it will lead to a disastrous outcome. This fallacy uses the emotions and shortcuts in reasoning to create fear. It does not provide justification for the chain of events and argues that the first event should be prevented at all costs to avoid the disastrous outcome.
When evaluating an argument ask yourself:
- Is the argument claiming a course of action will lead to undesirable outcomes in the future?
- Are reasons provided for each event along the causal path?
- Does the argument insist that subsequent events will occur without providing a clear reason?
This is also called the false dichotomy, false dilemma and either/or fallacy. This fallacy presents two options as if they are the only options. In doing so, other options are ignored, and the audience feels forced to choose between two extremes.
When evaluating an argument ask yourself:
- Are all possible options presented?
- If there are only two options presented, is a possible compromise between the two options being ignored?
This is often called the ‘straw-man fallacy’ because when an argument is oversimplified or misrepresented it becomes something that cannot stand up to scrutiny and is easily pulled apart or dismissed. It misrepresents someone else’s argument in a reductive way to make it seem the argument is not credible. This can involve exaggerating an opponent’s position, focusing only on their weakest line of reasoning, or refuting something not even stated.
When evaluating an argument ask yourself:
- Is the value of someone else’s argument being underestimated or ignored?
- Are the limitations of someone else’s argument being exaggerated?
- Does the argument only focus on the limitations of someone else’s argument?
- Does the argument refute something that has not even been stated in the other argument?