Photo by Anna Moneymaker of The New York Times / President Donald Trump boards Air Force One at Joint Base Andrews, Maryland, before traveling to Clyde, Ohio, on Aug. 6, 2020.

Abraham Lincoln once said, "No man has a good enough memory to be a successful liar." To be a good liar you have to keep track of all the lies you've told, and to whom, in order to keep the truth hidden. But Honest Abe never knew President Donald Trump, or perhaps anybody like him.

Trump is a successful liar because he refuses to remember. Not only that: He refuses to anticipate that he will remember the current moment in the future. If you live mainly in the current moment, then the future consequences of your lies will not matter to you. And if you have lived your entire life this way, and to great acclaim and success, why would you ever want to change?

The president was recently annoyed when Dr. Anthony Fauci stole the spotlight by throwing out the first pitch for Major League Baseball's opening game. In response, he falsely claimed that the New York Yankees invited him to throw out the first pitch for Aug. 15. His assertion was roundly refuted a short time later.

The key to Trump's psychology is that he moves through life as what I call "the episodic man." For Trump, each day is indeed "a temporary moment of time." Psychological research shows that nearly all adults develop stories in their minds about their own lives. These stories — what psychologists call "narrative identities" — reconstruct the past and imagine the future to give people a sense that lives have meaning and coherence over time. As you make daily decisions, you implicitly remember how you have come to be who you are, and you anticipate where your life may be going. You live within narrative time.

But the episodic man does not live that way. Like a boxer in the ring, he brings everything he has to the immediate episode, fighting furiously to come out on top. But the episodes do not add up. They do not form a narrative arc. In Trump's case, it is as if he wakes up each morning nearly oblivious to what happened the day before. What he said and did yesterday, in order to win yesterday, no longer matters to him. And what he will do today, in order to win today, will not matter for tomorrow.

What is truth for the episodic man? Truth is whatever works to win the moment. The boxer faces an imminent threat to his survival. If he takes his eyes off the immediate aim of winning, he may get knocked out. Boxing his way through life, moment by discrete moment, Trump does not have the psychological luxury to consider whether his tactics comport with the conventional criteria for truth — such as consistency over time or concordance with the objective reality of the outside world. Every day is a war. All is fair.

Nearly 40 years ago, Trump conveyed his philosophy of life to an interviewer: "Man is the most vicious of all animals, and life is a series of battles ending in victory or defeat." Before he was sworn into office, Trump told his advisers to think about each presidential day as an episode in a television show in which he vanquishes rivals.

The show is not, however, a long-running drama that builds over time to a conclusion. Each day, instead, is like an episode of "Seinfeld," self-contained with its own beginning and ending, or like the opening-night game between the Yankees and the Nationals. Somebody will win (in Trump's mind it is always him). And then we start all over again tomorrow.

For most people, and every other president in the history of the United States, an episodic life would be unsustainable in the long run. But for Trump, it has always been a winning life strategy. His admirers appreciate his total engagement of the moment. He brings it all to the battle today. There is a primal authenticity in Trump. He tells you exactly what he feels in the moment. He lies straight to your face, without shame, without any concern for future consequences. It is the stark audacity of untruth.

Dan P. McAdams is the Henry Wade Rogers Professor of Psychology at Northwestern University and author of "The Strange Case of Donald J. Trump: A Psychological Reckoning."

The Los Angeles Times