TANSTAAFL, Time Travel, and the Price of Progress

Welcome to the first post of 2025! January always seems to bring a heightened awareness of time and its relentless march forward. As we flip to a fresh calendar, it’s hard not to reflect on where we’ve been, where we’re headed, and the infinite possibilities time holds—whether measured in the ticking of a clock or the grand, mind-bending journeys of science fiction. There’s no better moment to dive into the fascinating concept of time travel and the costs that come with bending the rules of the universe.

I’ve always loved time travel. My fascination with the concept began early—H.G. Wells’ The Time Machine introduced me to the idea when I was six or seven years old. But that early exposure also ruined me for certain aspects of time travel fiction.

Here’s why: in science fiction, everything has a cost. Heinlein’s famous acronym TANSTAAFL—“There Ain’t No Such Thing As A Free Lunch”—is practically a law of the genre. For those unfamiliar, TANSTAAFL boils down to this: no matter how wondrous or advanced something might seem, there’s always a price to be paid. Whether it’s physics, resources, or ethics, the bill always comes due.

Robert A. Heinlein applied TANSTAAFL not only to his characters’ decisions but to every facet of his worldbuilding. His stories hinge on the principle that when something appears too good to be true, it probably is. And he wasn’t alone. Science fiction as a genre thrives on a bedrock of logic and extrapolation, pushing the boundaries of science to its limits but never straying so far that the story feels weightless or ungrounded.

Arthur C. Clarke put it another way: “Any sufficiently advanced technology is indistinguishable from magic.” Yet even magical-seeming tech must follow its own internal rules, derived from science or the story’s logic. In the best science fiction, nothing comes without consequences.

The Cost of Technology

Take space travel. When Apollo 11 went to the moon, it required three days cramped inside a fragile tin can with immediate, omnipresent danger—vacuum, radiation, and human error—held off only by the most stringent protocols. The greatest accomplishment of that journey wasn’t the moon landing itself but getting the astronauts back home.

Compare that to Star Trek’s Enterprise, which zips to the moon in seconds. But even here, the cost of advanced technology is apparent: Klingons waiting to pick a fight, troublesome Tribbles clogging up the works, and interpersonal drama aplenty. And in The Next Generation, technological progress gives us peace with the Klingons—but also the Borg, a relentless reminder that convenience and power invite new and terrifying challenges.

In science fiction, every invention, every capability, comes with a drawback. That tension is part of what makes the genre so compelling.

Time Travel Without Consequences?

This is why certain time travel stories leave me squirming. You know the ones: characters casually hop a thousand years into the past or future, stepping through time as though walking through a doorway, facing no ill effects, and leaving no ripples in the fabric of history.

To my mind, that violates the spirit of science fiction. Time travel should come with limitations, costs, and consequences. How does the act of traveling affect the traveler? The environment? The timeline itself? Exploring those challenges makes the story richer and far more compelling.

In my own time travel stories (which I write under a different pen name), I’ve made a point to grapple with those questions. The mechanics and repercussions of time travel are integral to the worlds I build. There’s no free lunch—especially when it comes to altering time.

Consequences in Time Travel

For example, consider the mechanics of time travel in H.G. Wells’ The Time Machine. In Wells’ world, the Time Traveler is able to navigate through time using a carefully constructed machine. But even with the device’s precision, the journey is fraught with risks and consequences. When the protagonist travels forward millions of years, he discovers a world so alien that human evolution has diverged into entirely different species. The price of his journey isn’t physical harm but rather the sobering realization of humanity’s fragile and transient place in the universe.

Or take the Back to the Future trilogy, where the iconic DeLorean can zip through time—if you have plutonium (or lightning) to power it and can hit precisely 88 miles per hour. Yet time travel here isn’t without cost either. The timelines themselves are fragile, susceptible to cascading effects from even the smallest interference. Marty McFly’s attempts to save his family from disaster repeatedly create new problems, underscoring the idea that meddling with time is never simple and always carries unforeseen consequences.

In both examples, time travel becomes more than a tool; it’s a narrative force that adds complexity and tension to the story. The consequences are what make the journeys meaningful—and believable.

Why the Price Matters

By embedding consequences into time travel—whether it’s a fractured timeline or the eerie realization of a distant future—we elevate the stakes and create richer stories. Without those repercussions, time travel risks becoming a deus ex machina, a cheat code that solves problems without effort or cost.

This is why TANSTAAFL is such an essential concept in science fiction. When time travel comes with a price, it becomes more than just a mechanism for moving characters around—it shapes the narrative itself. That tension, born of limitations and consequences, is where the best science fiction thrives. It’s what transforms an intriguing premise into a story that lingers in the mind long after the final page or scene.

Time travel without consequences? That’s just an empty contrivance. Heinlein’s principle reminds us that every journey, no matter how wondrous, must come with its cost. And the story is always better for it.

What are your favourite time travel stories? Tell me in comments — I’ve no objection to increasing my TBR pile. 🙂

Latest releases:
Ptolemy Lane Tales Omnibus
Galactic Reflections
The Return of the Peacemaker
He Really Meant It