Reason & Argument (DP IB Theory of Knowledge): Revision Note

Reason & argument

Reason

• Reason involves using logic and inference to move from ideas to conclusions in a structured way:

  • Knowers use reason to check whether beliefs are coherent and consistent with each other

  • Knowers can connect different pieces of evidence to form explanations and make predictions

• The importance given to reason can vary across cultures, disciplines and personal worldviews

Argument

• An argument is a statement that provides reasons for or against accepting a conclusion

• Arguments are used when knowers want to:

  • justify a claim 

  • challenge a claim 

  • persuade others to change their minds about a claim

• Arguments appear in everyday life, in academic disciplines, in the media and in ethical or political debates

• The arguments used by an individual may be shaped by:

  • purpose, such as whether someone want to inform, persuade or defend

  • audience: people may choose reasons they think will be most convincing to a particular group

  • background: culture, personal values and academic discipline can shape what counts as a good reason in an argument

Developing arguments: validity, soundness and strength

• When knowers develop an argument, they can use validity, soundness and strength to check how clearly and effectively their reasons support their conclusion

  • Validity focuses on the logical link between reasons and conclusions

    • An argument is more valid when there is a clear, step-by-step connection between each reason and what the knower wants the audience to accept

    • Testing for validity helps knowers spot gaps in reasoning, such as jumping to a conclusion that does not really follow from an argument

  • Soundness incorporates validity, but is also about whether the reasons within an argument are true:

    • A sound argument uses reasons that are accurate, relevant and not misleading in the way they are presented

    • Soundness helps knowers avoid using weak, exaggerated or selective reasons just because they support a preferred conclusion

  • Strength focuses on how convincing the overall support is for the conclusion

    • A stronger argument uses enough well-chosen reasons and evidence for the situation and audience

    • Strength helps knowers build arguments that are coherent and that will allow an arguer to respond to questions or objections

Fallacies and bias in reasoning

• A fallacy is a pattern of reasoning that seems persuasive but does not genuinely support the conclusion; common fallacies include:

  • attacking the person instead of the claim

    • E.g. “you are bad at science, so your argument about climate change must be wrong” 

  • assuming that because B follows A, A must have caused B

    • E.g. “I wore my lucky bracelet and then passed the test, so the bracelet made the difference”

  • presenting only two options when more than two exist (false binary)

    • E.g. “either you support this policy completely or you do not care about poverty”

• Biases can lead knowers to accept weak arguments that support their existing views, e.g.:

  • the knower may look for, notice or remember information that supports what they already believe (confirmation bias)

  • dramatic or recent events feel more common than they really are because they are easier to recall

  • the knower favours people from their own group, culture or community, and chooses to believe their arguments, or even only listen to their arguments and not to others’ outside their group (echo chamber, epistemic bubble)

• Recognising fallacies and biases can be seen as an ethical responsibility when we argue in public, academic or professional contexts