Arguments on Stone Supports

In the picture

1. 1The level left slab: a conclusion supported in a valid form.
2. 2The front left pillar on bedrock: a true premise.
3. 3The back left pillar on bedrock: a second true premise.
4. 4The tilted right slab: a conclusion whose form is not valid.
5. 5The right pillar sunk in sand: a false premise.

Examples

• All humans are mortal. Maria is human. Therefore Maria is mortal.
• All fish can fly. A salmon is a fish. Therefore a salmon can fly.

Quiz: Arguments on Stone Supports (Age 15)

1. 1

   What must be true of a sound argument?

   • It has a convincing conclusion, even if some premises are false.
   • It has a valid form and all its premises are true.
   • It has at least one true premise, even if its form is invalid.
2. 2

   What do premises do in an argument?

   • They make the argument sound even if false.
   • They are the conclusion being proved.
   • They support the conclusion.
3. 3

   How strong is a conclusion compared with the premises supporting it?

   • It is always stronger than the premises supporting it.
   • It does not depend on the premises supporting it.
   • It is only as strong as the premises supporting it.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.