Space-Time May Not Exist the Way You Think

Right now, you exist. The chair you sat in yesterday also occurred. Those two statements sound the same, but they are not, and the difference between them sits at the heart of a problem that has quietly haunted physics for over a century. A new analysis published through The Conversation by Daryl Janzen, Observatory Manager and Instructor in Astronomy at the University of Saskatchewan, argues that physicists have been blurring this distinction when they talk about what space-time is, and the confusion runs all the way to the foundations of how we understand reality itself.

The Word at the Centre of a Century-Old Confusion

Ask any physicist what holds the universe together and many will say: space-time. It is described as the fabric of reality, the invisible four-dimensional structure in which every star, planet, and person is embedded. Einstein's theory of relativity showed that space and time are not separate things but are woven into a single flexible sheet, one that bends and stretches in response to gravity.

So far, most people can follow. The confusion begins when physicists go further and start saying this fabric "exists." That word, Janzen points out, carries enormous hidden baggage. And nobody seems to have noticed.

The philosophical problem Janzen identifies is not about whether Einstein's equations are right. They are, and no experiment has ever seriously contradicted them. The problem is about what language physicists use when they interpret what those equations describe, and whether that language actually makes sense.

What Is the Block Universe and Why Does It Matter?

To understand the issue, you need to know about one of the most widely accepted ideas in physics: the block universe.

Picture a novel. Every page, every sentence, every word already exists inside the book, all at once, whether you are currently reading page 3 or page 300. Nothing in the book is "happening." It is all just there, frozen, waiting. The block universe says reality works exactly like that novel. The entire history of the universe, from the Big Bang to the far future, is already laid out in a fixed, four-dimensional structure. What we experience as the "flow" of time, as moments passing one by one, is an illusion. Everything that ever was, is, or will be already exists simultaneously in the block.

This is not a fringe position. Many of the world's leading physicists accept or lean toward the block universe interpretation. It follows naturally from how Einstein's equations treat time as a fourth dimension alongside the three of space. And it shapes how scientists imagine everything from time travel to the Big Bang to the question of whether the universe had a beginning at all. But it rests on a word that Janzen says nobody has properly defined: "exists."

What Is the Difference Between Existing and Occurring?

Here is where the argument gets surprisingly concrete. And once you see the distinction, it is impossible to unsee.

An elephant standing in the room with you right now exists. It has mass, it takes up space, and it endures through time. If you came back in five minutes, the elephant would still be there. That is what it means for something to exist. Now imagine a single photographic frame taken of that elephant, one frozen millisecond of its life. That frame does not exist in the same sense. It merely records something that occurred.

Now apply this to space-time itself. The block universe claims that all of eternity, every event across all time, exists simultaneously in a four-dimensional structure. But if everything just occurs as a set of frozen moments rather than enduring through time, then space-time is not a thing that exists in the way the elephant does. It is more like an enormous catalogue of all the occurrences that ever happened, with no more active existence than a completed photograph album.

The problem cuts even deeper. For the block universe to produce even the illusion that time passes, it must itself endure in time like the existing elephant, not simply occur like the frozen photograph. But the moment you say that, you have quietly added a layer of time on top of your supposedly timeless structure. The block universe was meant to contain all of time. Now it needs something outside itself to exist in.

Why Does This Problem Send Physics Into a Fifth Dimension?

Janzen takes the argument to its logical conclusion, and the destination is uncomfortable.

If you want space-time to exist in the full, proper sense, the way an elephant exists, then you need it to endure through time. But space-time is supposed to be the container of all time. So you would need to place your four-dimensional space-time inside a larger framework with an additional time dimension, making the full structure five-dimensional: three dimensions of space and two of time.

This is not a proposal to rebuild physics from scratch. Janzen is not suggesting that a five-dimensional universe is real. The point is sharper: the instant you try to give space-time the kind of full, genuine existence we assume it has, you find that you cannot do it without smuggling in an extra dimension that current physics does not include. That is a sign the concept has not been properly thought through.

The comparison to film and fiction is instructive. In The Terminator, the timeline is fixed and cannot be changed, matching the block universe perfectly. In Avengers: Endgame, characters travel back and alter history, which only makes sense if four-dimensional space-time itself exists the way a physical object does, capable of being modified. Neither film stops to ask what kind of existence the timeline has. Neither has physics, until now.

What This Means for How We Understand Reality

Janzen is careful about what his argument does and does not claim. Einstein's equations are not broken. Relativity works. GPS satellites still use it to keep accurate time. The mathematics is not the problem.

The problem is interpretation. How we talk about what space-time is shapes how physicists approach the deepest unsolved questions in the field, including how to reconcile general relativity with quantum mechanics, whether time had a genuine beginning, and whether the past and future are as real as the present.

• Einstein's equations still work — this argument does not challenge the mathematical theory of relativity or any experimental result that supports it.
• The word "exists" has been doing hidden work — physicists have treated existence and occurrence as the same thing for over a century without noticing the assumption.
• The block universe has an unresolved problem at its core — for time's flow to be an illusion, space-time must itself endure in time, which is precisely what the block universe says it does not do.

"Defining space-time is more than a technical debate — it is about what kind of world we think we are living in." — Daryl Janzen, The Conversation, June 2026.

The question of what space-time is might seem remote, the kind of thing only professors debate in academic journals. But it is actually the most personal question in physics. You are reading these words inside space-time right now, carried forward by something that science calls the flow of time. Whether that flow is real, or an illusion created by a frozen block of eternity, or something that language has simply failed to describe properly after all this time, that question is not just about the universe. It is about whether the moment you are living in right now actually exists at all.