Critical Thinking

Event Type
Web Session
The UCD Centre for Ethics in Public life (CEPL)

Start time: 3.00 pm

End time: 5.30 pm


Announcements from the UCD Centre for Ethics in Public life (CEPL) organiser: Reasoning is easy, but reasoning well is hard. Reasoning well means being sensitive to the evidence in such a way that our beliefs are more likely to be true. But when we are tired, or hungry, or emotional, or want to fit in, or already have an opinion, we are apt to reason badly. This online interactive seminar, provides a philosophical introduction to good reasoning. The 2.5 hour online seminar consists of a mixture of short lectures and group discussions, and offers theoretical and practical guidance on how to reason well. Participants will receive general readings in advance of the course, and will be given the opportunity to complete an assessment with feedback afterwards.

In the seminar we will address two broad questions: first, what are the common forms of bad reasoning, and how can we avoid them (or at least, take them into account)? Second, what does it mean to reason well, and to be sensitive to the evidence?

Part I

Research in cognitive psychology and behavioural science over the last number of decades has revealed the extent to which we are subject to cognitive biases: predictable patterns of bad reasoning. For instance, we are subject to the framing effect: many more people would opt for a surgery with a 90% success rate than a surgery with a 10% fatality rate. More generally, it has been shown that reasoning is an energy-intensive process that we are apt to perform badly when we are tired, hungry, emotional, already have an opinion, or simply want to fit in with our perceived peers. Even worse, usually we will not realise that we are reasoning badly; and we will continue to defend the beliefs we form as a result of our bad reasoning, on the grounds that changing one’s mind is a sign of weakness or unseriousness (think of politicians who are accused of ‘flip-flopping’). In the first part of the seminar, we will look at some of the common forms of cognitive bias, as well as common forms of bad argument (fallacies). We will also consider the sort of mindset that characterises a good reasoner.

Part II

When we reason well, our assumptions (premises) bear a certain important relation to the beliefs we form on the basis of our reasoning (conclusions): they provide inferential support for them. Inferential support comes in two flavours: deductive and inductive. When our premises provide deductive support for our conclusions, the truth of our premises guarantees the truth of our conclusions. Logic is the study of deductive support. When our premises provide inductive support for our conclusions, the truth of our premises make the truth of our conclusions more likely than not, without guaranteeing them. In that case, we say that our premises provide evidence for our conclusions. In order to reason well, we must understand the notion of inferential support. We also want to be able to assess arguments (i.e. instances of reasoning) that are presented to us. In order to do that, we must learn how to identify premises and conclusions, and to reconstruct arguments in order to test their inferential strength. In the second part of the seminar, we will learn about arguments; inferential support; and evidence. We will then describe a strategy for reconstructing and testing arguments.

Cost: €25 – €75 . Click here to make a reservationA zoom link will be emailed to you once you have registered and paid.

Any queries please contact Fiona Lavin at

  • Introduction and warm up (10 minutes)
  • Presentation: Cognitive Biases & Mindset (20 minutes)
  • Discussion (10 minutes)
  • Presentation: Fallacies (20 minutes)
  • Discussion (10 minutes)

Break (10 minutes)

  • Presentation: Argument Structure (25 minutes)
  • Discussion (10 minutes)
  • Presentation: Argument Reconstruction (20 minutes)
  • Discussion and wrap-up (15 minutes)
Dr. Daniel Esmonde Deasy from the UCD School of Philosophy