The corners of a geometrically perfect square should have no width. But if they have no width they don't exist. Therefore the corners must have a width. If they have a width they can be looked at as additional sides. look at this picture

  • The probability for anything to happen at an exact point in time (point-probability in a continuum) is exactly nil, does that mean nothing ever happens? How is this anything but a word-play with ambiguous terms like "exist"? Also, please be aware that questions that involve the evaluation of an argument made by the OP are generally considered off-topic here.
    – Philip Klöcking
    Jan 4, 2021 at 21:54
  • How does the linked picture illustrate the question? What does it mean to say that the corner of a square has or does not have a width? Jan 4, 2021 at 21:54
  • what is the op ?
    – user49811
    Jan 4, 2021 at 21:55
  • 1
    "Original post", it means your question.
    – armand
    Jan 4, 2021 at 21:58
  • 2
    This is an antimony or paradox of any idealized object, the same reason you can't "square the circle." Points exist in space and (spatially) do not... at a given "place" with a nonexistent precision. In Newton's calculus mapping measurable points onto curves required an infinite regress towards the point with an arbitrary "limit" given to any degree of precision. Many at the time disliked this infinitesimal "fudge factor," which Berkeley called "the ghosts of departed quantities." This idea of something dimensionless or "infinitely precise" is source of many paradoxes. Jan 5, 2021 at 0:42

3 Answers 3


Why not also argue that a perfect three-dimensional body is not conceivable, because it needs to be bounded by a surface, which has zero width and therefore does not exist? If the surface does not exist, then the body also cannot.

That's somewhat similar to Zeno's argument that there cannot exist many things.

I admit that the human mind can get entangled into certain "problems" when thinking about perfect geometric forms. If we take away the corner points of a perfect square, say, remove the single points (0, 0), (1, 0), ... of the unit square, have the square's corners gone blunt or is it still perfect? Or more fundamentally, does it still have corners?

But this can at least be mathematically handled so is it really inconceivable?

And even if it is, can we make the step "inconceivable" => "impossible"? This inference has a long tradition but is not unequivocally accepted.

  • I don't understand the first thing that you said. The surface of of a three dimensional object has measurements in two dimensions whereas a point has no measurements in any dimensions.
    – user49811
    Jan 5, 2021 at 1:53
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    But a point is not a physical object, so it's irrelevant if you can measure it or not.
    – armand
    Jan 5, 2021 at 2:54

The question is somewhat biased on perception.

The corners by themselves have no significance. Corners are formed only when two line intersects. Now if we are talking about geometry any corner do not have a width because it's not an object by itself but just a name given to identify a point in space.

Now if we talk about perception, by definition a dot is a small round mark or spot. However if you see a dot or a circle on your computer screen is it actually round? The answer is that you perceive those things as round but in fact they are made out of small square shaped pixels.

Therefore we can say that corners do not have width according to geometry and by perception if we go to say like it got 0.00000000001 width which in itself got no significance


Perfection and existence are different issues. A boundary can exist as the junction of two other things which exist, even though it has no independent physical existence.

But your question title asks something rather different. A perfect square cannot physically exist. The reason for this is not any problem with the existence of its boundary, rather it is in the imperfection of its boundary. Due to the finite size of atoms, quantum fluctuations and other phenomena, no physical object can perfectly align with a mathematical square.

Plato proposed an independent world of ideals, in which the perfect square did exist, but it rather begs the question as to what we mean by existence.

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