Anchor: For case studies in particular, there must be an empirical basis for instance selection and assurance of adequate population homogeneity.
Entailed: When selecting instances there needs to be an empirical basis for the purpose of the case study.
Contradiction: The case study doesn't necessarily need to have an empirical basis for the selection of instances.
Contradiction: Dogs never need to go to the vet at all.  
Contradiction: There is a mural on the side of a building.
Contradiction: They didn't stop, so it was easy to find them.
Contradiction: A younster is playing with a toy.