Martin Winterkorn resigned as chief executive of Volkswagen yesterday, after a major scandal rocked the company. The company has admitted to manipulating technology to dodge emissions regulations. Winterkorn continues to insist that he didn't know anything about the impropriety, though he did take responsibility and step down as chief executive. Could it be possible that he didn't know? Some would say that he must have known. Naturally, we have no idea whether he's telling the truth. We will have to wait for a full investigation to be completed. However, I would like to suggest that it is possible that Winterkorn did not know. Why? Volkswagen, like many companies, may have had a culture where people were afraid to share bad news with senior executives, and afraid to speak up when they disagreed with key decisions being made. Of course, Winterkorn is responsible for the culture. If people didn't share the bad news with him, we have to ask whether he cultivated a climate in which people were afraid to speak up. Did he do enough to reach out and invite people to share bad news, express dissenting opinions, and disclose risks? The leaders of any organization ultimately are responsible for creating that safe space and for encouraging people to speak up. Leaders need to do more than have an open door policy. They have to reach out and try to uncover hidden risks. They have to become problem finders.