An analogy proposes that two concepts which are similar (A and B) have a common relationship to some property. A has property X, therefore B must also have property X. In a false analogy, the objects may have some similarities, but they do not both have property X. That way, both objects may have the same color, but this does not mean that they have the same size. Even if bananas and the sun appear yellow, one could not conclude that they are the same size. One who makes an invalid analogy or comparison is often said to be "comparing apples and oranges".