Misunderstandings often develop when scientists from different backgro
unds use the same words (e.g., ''selection'') when they mean different
things by them. Theorists must therefore choose and define their term
s carefully. In addition, proponents of ''new'' theories need to demon
strate empirically that theirs are more powerful than the existing the
ories they wish to supplant. Wilson & Sober have not yet done this.