Some of my favorite sci-fi stories involve time travel.

Back to the Future was a fun and silly adventure when I was younger. The first episode of Star Trek: The Next Generation that I remember clearly involved an alternate timeline created by a starship accidentally traveling through time. Later, movies like 12 Monkeys and Terminator 1 & 2 echoed elements of some of the classics I read in high school English, like Oedipus. We also read the short story that captures the meaning of the term “Butterfly Effect.”

These all posed questions like, “If you know the future, can you change it?” Or “If you can travel to the past, could you affect the present?”

Though it can be fun to wonder and read stories that give possible answers, we may never know. Time travel seems impossible.

Even so, it’s something I look for when critiquing a piece of writing.

By that I mean I look for changes between past and present tense.

One of the fundamental decisions a writer makes is selecting the tense of the piece. Will this be written in present tense – actions as they happen – or past tense – actions completed?

Which one chooses doesn’t matter so much. (I mean, yes, of course there are debates that could go on about what tense is best for which genre, for which POV, for which type of story, and so on.)

What matters is consistency. The tense cannot change mid-sentence, mid-paragraph, mid-article, mid-chapter, mid-novel. Writers can give us glimpses into other times through their creativity and skill, but they must not make us travel through time through failure to maintain the verb tense of their piece.

Consider this example:

I looked across the room and my eyes met hers. She walks over to my table and introduces herself. “Hey there,” she said. “My name’s Amanda.” Her lips part into a sultry smile and she winks at me.

Pick a tense and stick with it. All past tense completed, or all present tense as it happens.

Most often, I’ve seen first person POV writing use the present tense.

I turn to him and level the gun at his face. “You can’t take her,” I say, “unless you go through me.” The hammer clicks back. His look tells me he doesn’t think I’ll do it. Then he lunges.

I close my eyes and pull the trigger.

The idea here is that, like life, we see what’s happening as the POV character does. We react to emotions and events because we’re in the passenger seat right next to them as this roller-coaster plot careens down the tracks. It can make for interesting action, though first person POV comes with its own set of challenges.

Certainly a first person work could tell the story in the past tense. A personal account of an experience as an example in a self-help article is an instance of this kind of writing. It’s the friend sitting over tea saying, “Have I told you what happened to me twenty years ago? Well, I struggled with self-loathing for years, and it got to the point that I considered…”

I’m personally not a fan of a novel or fiction story written in first person past tense unless done exceptionally well. I don’t like the idea that the character in the book is recounting to me the way things happened in his or her story. (For one, that’s almost always a good spoiler clue this character survived whatever conflict the story contains.) I’m not saying it’s impossible, just less common.

For third person works, most often I see verbs in past tense, actions completed, events written as though they already happened long ago.

She turned to him and leveled the gun at his face. “You can’t take her,” she said, “unless you go through me.” The hammer clicked back and she noted the sneer in his smile. He doesn’t think I’ll do it.

He lunged at her.

She closed her eyes and pulled the trigger.

Even though all these actions are written like they happened in the past and the conflict is already resolved, our brains process the story like it’s happening now because we don’t know what happens — er, what happened next.

So what might seem like a boring, conflict-already-settled choice actually creates a dynamic tension in the reader. It’s just like how no one watches a movie thinking, “Well, this story has already been filmed completely. The ending is set. All these events already happened.”

Third person present tense is also an option not commonly seen, but possible to pull off with great skill.

She says to him, “We aren’t meant to be together.” So he grabs her arm, demands her affection one more time, and counts off all the reasons she ‘owes’ him.

She slaps him across the face so hard his nose starts bleeding. The other women in the room spontaneously cheer and give her a standing ovation as she stalks off.

To me this has the feel of a guy at the bar telling a wild tale. “You wouldn’t believe what I just saw happen.” I’m not a fan.

Past tense is generally preferred in 3rd person.

But sometimes a sentence may start with a past tense completed verb then show an ongoing action: “She thrust the spear at the bandit, yelling a formation command to her troops.” Even in that case, it’s clear that the action happened in the past, and another action was happening at the same time. It’s a way of depicting what’s going on in the “present” moment of the past tense story.

I’ve heard both sides of debate that such a formation is wrong or acceptable. I personally use it. And I don’t care one way or the other.

The only thing I’m looking for as far as verb tense is concerned is consistency. I’ll borrow a David Tennant Doctor Who quote here:

The Doctor: People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint – it’s more like a big ball of wibbly wobbly… time-y wimey… stuff.

No, it’s not. Not in good writing. Broken verb tense creates a mess even the Doctor cannot fix.