Answer:
The principle is Family Resemblance.
Step-by-step explanation:
Family Resemblance is understood as the idea that objects are similar to each other because a common feature may seem a certain way because of various shared similar features which overlay one another.
This is the case, most individuals tend to be able to recognize a variety of examples of chairs because they tend to have similar features even though, as the example states, not all chairs have 4 legs.