In another class - thinking about identity, vagueness and sets

This session began life as an extension activity to The Ship of Theseus session (see The If Machine p. 86) but has now developed into a session in it’s own right. It’s a good get-up-and-do session.

Equipment needed and preparation: space, a class of children

Starting age: 8 years

Key concepts / vocabulary: change, identity, same, at what point, borderline, black-and-white-thinking, different,

Subject links: Maths, PSHE,

Key controversies: At what point, if at all, does something become something else?


Critical thinking tool: Evaluation – in P4C it is sometimes believed by teachers, practitioners and the children that ‘there are no right and wrong answers’. One of the most overlooked aspects of critical thinking is the need to make judgments; in other words, to decide what argument or idea one thinks is right, according to the quality of reasons given. In his On Rhetoric Aristotle describes three ways that one may persuade: ethos, pathos and logos. Ethos is the appeal to the authority or credibility of the presenter, pathos is the appeal to the emotions of the listener, and logos is the appeal to reason. Philosophy’s focus is logos.

Key Facilitation Skill: Invite persuasion (logos) – sometimes the dialogue lends itself to making evaluative judgments. For example, if two children hold opposite conclusions. Imagine one girl says that the ‘Class A’ is now where ‘Class B’ was because ‘that’s where all the people from ‘Class A’ are now’, and a boy says, ‘The one that started as ‘Class A’ is still called ‘Class A’ so that’s still ‘Class A’ even though all the children have moved.’ You could invite them to try to persuade (logos) the other that they are right. This invites them to dig deeper in order to provide a more powerful argument. You could ask other members of the class to see if they can persuade (logos) others that either the girl or the boy are right. Never tell the class who you think is right, though. This approach reminds the class of three things: 1) that judgments can be made and 2) that when judgments are made they are made on the quality of the arguments and 3) to make better arguments.


Session Plan:

1) Have the class stand up.
2) Split the class into two (equal or as close as).
3) Have them stand in two circles or two lines opposite one another.
4) Name one group ‘class A’ and the other ‘class B’.
5) Ask everyone to begin by putting their thumbs up.
6) Ask them to put their thumbs down when they think the class is no longer the same class.
7) Tap two children (one from each ‘class’) on the shoulder and have the two children swap places, joining the other class.
8) Tap another two children and have them do the same.
9) Carry on in this way until all the children have swapped classes.

Task Questions:

  • If you changed your thumb direction, at what point did you change your thumb direction?

  • Why did you change your thumb direction when you did?

  • Why didn’t you change your thumb direction?

  • Which is Class A and which is Class B?

Nested Questions:

  • Is there a point at which something becomes something else?
  • Are there reasons why something remains the same thing no matter what changes occur? If so, what would they be?
  • Can change occur without loss of identity?


Extension activities:


1) Find out the name of the class (e.g. ‘Oak class’ or ‘4RD’ etc.)
2) Ask the children where they went on their holidays.
3) Ask them to imagine drawing a line from X (e.g. Scotland) to Y (e.g. Mexico) etc. forming a big imaginary circle on a map.

Task Question: While you were all on your holidays how big was ‘X’ class?

Nested Questions:

  • Did ‘X’ class still exist?
  • When you are in the classroom does ‘class x’ still exist?
  • When you leave the classroom does ‘class x’ still exist?
  • What is a class?
  • Where is a class?

Big or small?

1) Have the class huddle up as close as possible to each other in the middle of the room.

Task Question: Is the class smaller?

2) Have the class spread out to the walls of the classroom as far as they can?

Task Question: Is the class bigger?

Nested Questions:

  • See Holidays! above


Related Resources:

Once Upon an If: As Clear As The Edge of a Cloud (pp. 61-62)
The If Machine: The Ship of Theseus, The Rebuild,
The If Odyssey: The Storyteller, The Stranger
The Philosophy Shop: Metaphysics: Personal Identity, A Heap of Exercises? (The sorites paradox), Across The River and Into The Trees, Tralse, Said and Unsaid.

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