Materials needed: Paper and pen/pencil

Description: Begin by having a loose discussion about the difference between “opinion” and “knowledge.” This should bring up claims about reasons, evidence, and proof. After a brief discussion about this difference, have the students write down three things they know. For each statement, have the students write down their best reason for thinking its true. Encourage their three beliefs to be pretty different from one another. Have the students put a star next to the belief they are most confident about. Have the students turn and talk to a neighbor about what they wrote and why.

Bring the class back to a general discussion and ask for a few volunteers to write their starred beliefs on the board. Ask the class about what are some good reasons for thinking these beliefs are true. As examples of each come up, write on the board these categories of evidence: memory, testimony, experience, logical. (“Logical” is a flawed word for what philosophers usually call a priori justification. Since that can be a difficult concept, “logical” seems to be an imperfect, but workable stand-in.) Ask the students which of these kinds of evidence is most trustworthy and why. Ask which is least trustworthy and why.

On the board, write down three false beliefs. For example, “There is a purple elephant in the room;” “The moon is made out of cheese;” or “[Teacher name] is a robot.”

For each statement, ask the students how they know the claim isn’t true. This should connect up with the different kinds of evidence mentioned earlier. Ask the students if they know that these aren’t true, or if just have an opinion that they aren’t true.

Finally, ask the students to return to their starred belief and to explain why they think they know it to be true, as opposed to just having an opinion that it’s true. After a few minutes, ask for volunteers to share their reasoning.

If you have any extra time, ask the students, as a class, to try to come up with the belief that they are most sure of. Put contenders on the board and have the class vote. End with a discussion about why that belief earns so much confidence.