The quote "You say you can't? Then don't do it. That's all." from Cormac McCarthy's novel "The Road" reflects a straightforward perspective on personal capability and choice. It suggests that self-doubt or a lack of belief in one’s abilities can be a barrier to action. If someone believes they cannot achieve something, then the simplest response is to accept that and refrain from attempting it.

This statement serves as a reminder that personal agency plays a crucial role in our lives. It emphasizes the importance of mindset when it comes to taking action. If a person approaches a task with the belief that they cannot succeed, it is often easier to avoid the challenge altogether. Therefore, fostering a more positive and confident outlook can lead to more significant achievements and overcoming obstacles.