The Flatlander theme is used to explain why it is that our universe may be within not just 3 dimensions and with time as a mysterious add-on but a much more complex arrangement. For example, maybe our universe is 3D and time is a process within a 4D environment which itself exists in a 5D embedding space (real or not).
It may seem to us that the universe is infinite; that the principle of tortoises on the back of tortoises goes on forever. But this is simply a limitation of our understanding restricted by our immediate 3D environment and our dismissal of other possible realities .
The simple way to understand this is to imagine that you lived within one dimension. A line. As you can only go forward or backward, you have no idea that sideways exists ,and therefore the line appears to be infinite because you know nothing about a 2nd dimension and how it could form a circle (and not be infinite). String theory crosses this mental barrier but for some reason insists extra dimensions are curled up (ridiculous). The reason for this is that we cannot 'see' extra dimensions so they must be hiding (crazy idea). In a way they are.
Our universe seems to be 3 dimensional and so of course we cannot see any extra dimensions. However, this does not mean we cannot experience their effects upon us; and time is an obvious example. Imagine that you are a Flatlander living on a two dimensional plane. Any thing passing through the plane or interfering or adding to it would be inexplicable in the terms of that plane. For example if a ball passed through your plane you would only notice a widening and then deminishing circle (and not a ball although clever mathematicians might be able to model it).
If we exist in a 4 dimensional construct with time as an added dimension you should notice that atoms (say) have unlimited length (strings) extending from the past into the future. They are not just points or minature spheres, their physical state exists in an extra dimension it becomes a tube (with a tiny diameter) the whole Quantume world becomes a interlocked system of string like extensions into the 4th dimension until 'collapse' of individual parts.
Realise that our experience of such a state is at only and instant. A 'now' that is moving through the 4d dimensions. We call this 'now' movement 'Time'. But we also have to realise that tjis time seems to us to be open ended (Like our line dwelling individual we discussed earlier). We have very limited ways of understanding that our situation may not be within an infinte 3D universe with a time process. Like the 'line as a circle' our universe may well be curved not only as a sphere but as a sphere that takes space back to its 'circle' avoiding infinity.
Absolutely, John. Your idea has strong philosophical and cosmological weight already—it’s evocative and playful in its treatment of dimensions and perception. I’ve polished the structure, smoothed the transitions, refined clarity, and added a touch more precision while keeping your voice intact. Here’s a refined version:
AI s better explanation of my missive: -
The Illusion of Infinity and the Dimensional Blindspot
It may seem to us that the universe is infinite—as if the cosmic principle of “tortoises all the way down” persists endlessly. But this perception is a direct consequence of our limitations: our senses and cognition are confined to a three-dimensional existence, and we habitually dismiss realities beyond what we can immediately observe.
To simplify the concept, imagine living within a single dimension—a line. Movement is restricted to forward or backward. The idea of “sideways” is inconceivable. From this constrained perspective, the line appears infinite because there’s no framework for understanding a second dimension—one that could bend the line into a circle, removing the notion of infinity entirely.
String theory attempts to breach this barrier, proposing the existence of additional dimensions. However, it paradoxically suggests that these dimensions must be “curled up” to account for why we can’t perceive them—a notion that borders on absurdity. Just because we can’t see extra dimensions doesn’t mean they’re hiding. It’s more accurate to say we’re blind to them, like the Flatlander who cannot conceive of ‘up’ or ‘down’.
Consider the Flatlander again, living on a two-dimensional plane. If a three-dimensional object like a ball passed through, the Flatlander wouldn’t see a sphere—they’d observe a growing and shrinking circle. The true nature of the event is inaccessible from within their plane. Only abstract modeling could hint at the higher dimensional reality.
Now apply this logic to us. If we inhabit a four-dimensional construct where time is the fourth dimension, then physical entities—say atoms—would not merely be point-like or spherical. They would extend through time as thread-like structures, forming tiny tubes stretching from the past into the future. The quantum world, in this view, is a vast interwoven system of these temporal filaments, with wavefunction collapse representing a localized “pinching off” in this temporal structure.
Our experience of this four-dimensional world is a fleeting slice—a single “now” moving through the higher dimensional space. We label this motion through 4D as “time.” But like the one-dimensional dweller who mistakes a circle for a line, we assume this time is open-ended simply because we lack the dimensional framework to perceive its curvature.
Indeed, our universe may not be an infinite 3D expanse with an arrow of time. It may well be a closed hypersphere—space curving not only into itself but also through time, forming a higher-order dimensional loop. Such a topology removes the illusion of infinity and replaces it with a far more elegant, though less intuitive, architecture.