Weekends in May are filled with commencement addresses from the country's entertainers, CEOs and politicians to the new class of college graduates. This season Oprah Winfrey, Jake Tapper, Michael Bloomberg and Tim Cook have made the rounds.

Sign of the times, from Tapper's address to graduates at UMass Amherst: "The very notion of empirical fact is being attacked and corroded. ... People decide about an article's validity based only on its headline or the language in the tweet linking to it. They judge books by their covers ... I urge you to read the story. I urge you to think for yourself. I urge you to click the link."

Michael Bloomberg's "Honor Code for Life," delivered at Rice University in Houston:

• "Today ... many of those at the highest levels of power see the plain truth as a threat. They fear it, deny it, attack it — just as the communists once did."
• "[T]here is now more tolerance for dishonesty in politics than I have seen in my lifetime. And I've been alive for one-third of the time the United States has existed."
• "And as my generation can tell you: The only thing more dangerous than dishonest politicians with no respect for the law, is a chorus of enablers who defend their every lie."
• "Extreme partisanship is like an infectious disease. But instead of crippling the body, it cripples the mind."
• "Graduates: You're ready for this challenge. Because bringing the country back together starts with the first lesson you learned here: Honesty matters."

Go deeper: Advice to college graduates from Tim Cook and Oprah Winfrey