The quote "To a man with only a hammer, a screw is a defective nail" illustrates the limitations individuals might face when they rely solely on one perspective or tool. It suggests that if someone lacks the means or knowledge to approach a problem differently, they may dismiss alternative solutions as flawed. This highlights the importance of versatility and the need to adapt one's approach based on the situation at hand.

In the context of Orson Scott Card's collection "Masterpieces: The Best Science Fiction of the Twentieth Century," this line emphasizes the significance of open-mindedness and creativity in problem-solving. It encourages readers to expand their toolkit of ideas and methods, suggesting that true understanding and innovation come from recognizing and utilizing various approaches, rather than sticking rigidly to a single perspective.