Entrepreneurs act on what they believe is an opportunity. Because opportunities exist in (or create and/or generate) high uncertainty, entrepreneurs must use their judgment about whether or not to act. However, doubt can undermine entrepreneurial action. Therefore, a key to understanding entrepreneurial action is begin able to assess the amount of uncertainty perceived to surround a potential opportunity and the individual’s willingness to bear that uncertainty. The individual’s prior knowledge can decrease the amount of uncertainty, and his or her motivation indicates a willingness to bear uncertainty.