Skills Hub

How not to construct arguments

This page is taken from the University of Plymouth Critical thinking guide (2008) which has been adapted from Warburton, N. (1998) Thinking, from A to Z. London: Routledge

The following examples are intended to be a humorous guide showing how not to construct arguments. These examples should be easy for you to understand and will help you to appreciate sound and faulty logic. You can look out for these common errors when analysing academic texts at university and try to avoid these faults in your own arguments.

Error: Ignore alternative explanations

  • I become bad tempered if I have a hangover
  • I am bad tempered
  • Therefore I must have a hangover

Error: Be ambiguous

  • Thanks for offering to help me hammering in this fence post.
  • When I nod my head, you hit it.

Error: Use anecdotal evidence to make sweeping generalisations

  • My friend tried acupuncture and it worked.
  • Therefore acupuncture can cure anything.

Error: Make assumptions

  • The meal contains nuts, so the patients should not eat it.

Error: Think in black and white

  • The patient is either completely mad, or completely sane.

Error: Be inconsistent & contradict yourself

  • Some people prefer an early start, but everyone likes a lie in.

Error: Rely on dictionary definitions that are

  • Short
  • Vague
  • Superficial
  • Unrelated to the context of your work

Error: Assume correlations are causes

  • There is a strong link between people's shoe size and the size of their vocabulary
  • Therefore having a large vocabulary causes your feet to grow.

Error: Introduce 'red herrings' (irrelevancies)

  • Let's consider whether music should be taught in schools
  • My great grandmother used to send me to sleep by playing lullabies on the trombone

Error: Be economical with the truth

  • Only three severe adverse reactions have been recorded
  • [This week]


Error: Use emotive language

  • This kind of stupidity is the main threat to the health of our precious young people

Error: Present formal fallacies: the starting point's OK, but the conclusion doesn't follow

  • Witches keep black cats
  • The lecturer keeps a black cat
  • Therefore the lecturer is a witch

Error: Use unnecessary jargon:

  • The French modus vivendi is too laissez faire (The French way of life is too relaxed / laid back)

Error: 'kowtowing' (bowing low in extreme humility / being sycophantic), or being overly deferential to people with some sort of elevated status, accepting their ideas without criticism just because of who they are:

  • Nietzsche, who was really famous and wonderful and knew everything, said to take a whip when approaching a woman, so it's ok to hit your wife

Error: Use persuader words

  • Obviously we should follow every instruction issued by a doctor

Error: Make rash generalisations

  • From the two case studies, it is clear that this outcome is inevitable for measles patients

Error: Employ wishful thinking

  • Clearly sending all patients home at this stage will reduce the cost of care without significantly impairing the patients' recovery

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