The Principles of Critical Thought

My DayOne journal reminded me that I wrote this entry two years ago today. Given what’s happened in the world this year, it seemed appropriate to make it the first post for this year. I’m quite sure that this is not my original material, unfortunately, I carelessly omitted to note the source in my journal. So apologies to whoever it is I am ripping off and and Happy New Year to everyone.


Critical thinking is:

  • Questioning information rather than merely receiving it (trust but verify),
  • A constant skill applied to all knowledge and belief (not to be compartmentalised).
  • Not an exercise; but a tool for belief testing and filtering (defence against false beliefs).
  • Must be applied to yourself as well as others (self-question, self-test, self-critique).
  • Not radical scepticism (work out when information is enough to settle a conclusion).

Step 1: Check the facts (check multiple sources and evaluate their reliability).
Step 2: Check for biases and fallacies (your own and those of others).
Step 3: Consider alternative explanations of the evidence and test them.

  • Find the best defences of either side of a dispute and compare them.
  • Consider your existing background knowledge and endeavour to acquire more of it.
  • Rely on facts & evidence, not assumptions.
  • Update your beliefs when evidence goes against them.
  • Restate all your beliefs as probabilities; then justify those probabilities (or change them if you can’t).