Fanciful ideas of time travel to the past were dispelled by modern philosopher Ned Markosiah at Tuesday night’s “Philosophy Today” lecture.

“So my argument is that time travel to the past is not possible if a certain theory of time is true. Namely, the dynamic theory of time, which I do think is true,” Markosian, a philosophy professor at Western Washington University, said. “So, I do think time travel to the past is not possible. As for time travel to the future, that could still be possible.”

The talk compared two competing schools of thought about time: static time and dynamic time.

According to static time, all times are equally real. So what happened a few days ago still exists in the same way as what is happening right now.

According to dynamic time, time is like a moving spotlight that shines on certain moments, and only the moments that are under the light exist. The spotlight keeps moving and cannot be stopped, just as time cannot be stopped.

Markosian said time travel to the past is impossible according to dynamic time theory for several reasons.

The first relates to theories of time travel involving scenarios where external time and personal time do not line up. Personal time is the time as experienced by the time traveler, and external time is the time of the rest of the world. His argument states that personal time is not really time at all; it is just a different sequential order without metaphysical implications.

His second reason for why time travel to the past is impossible is that present events cannot be causes for past events. As Markosian said, one cannot push a button today that made something happen in 1900.

“I’ve always been interested in the philosophy of time and issues like the static theory versus the dynamic theory, and then I think, like literally everyone, I find the idea of time travel fascinating, so that got me wondering, ‘Yeah, but is it really possible?’, and then applying some stuff about the different theories about the nature of time and then came up with the conclusion that time travel to the past is not possible if the dynamic theory is true,” Markosian said.

Reactions to the talk ranged from philosophical to emotional.

“I was kind of depressed to find out that time travel wasn’t real because it sounds super cool,” Damon Stanley, a junior majoring in math and philosophy, said.

Other students were intrigued by the theories of time discussed.

“I think I’d want to be a static time traveler because that seems kind of cool, but I think the intuitionism behind dynamic time travel is ballin’,” Matt O’Brien, a junior majoring in philosophy and economics, said. “I like intuitions as far as like, ‘Hey, go with what you think’s right until reason overruns it,’ and so right now, my intuition doesn’t go with static time, it goes with dynamic time, and I don’t have enough of a reason to want to time travel so bad that I should become a static time theorist.”

Markosian said if time travel were possible, he would like to go back in time to meet the ancient Greek philosophers Socrates, Plato and Aristotle.

“The difficulty would be learning ancient Greek,” he said.

Markosian’s and other “Philosophy Today” talks are available on iTunes U.