Consider an object - say 'a rock', for example.
Keep dividing it until you are left with just one particle. It doesn't matter what this particle is - the importance of the argument is to isolate an absolutely singular entity.
Some might object: "What happens if all objects are infinitely divisible?"
The simple answer to that is that if this is the case, then no singular finite objects actually exist in reality.
Either they do or they don't. If they don't, then bang goes your reality of singular entities separated by spacetime. If they do, then let's proceed with the argument:-
What can we say about an absolutely singular entity?
An absolutely-singular entity must be indivisible. Clearly, if it was divisible, then it could not be classed as an absolutely-singular entity in the first place.
Therefore, an absolutely-singular entity is absolutely indivisible.
What can we say about absolute indivisibility?
Space and time are what are reported to exist between singular entities (thus separating those entities). But neither space nor time can separate something that is reported as absolutely-indivisible.
Consequently, an absolutely-indivisible entity must, IN itself, be spaceless and timeless.
Conclusion
You must now see where this is going: If an absolutely singular entity is spaceless and timeless in itself, then those entities are not 4-dimensional in themselves.
In a nutshell: no "singular thing" can truly exist as a 4-dimensional entity = there is no 4-dimensional reality.
4-dimensional reality negated.
Keep dividing it until you are left with just one particle. It doesn't matter what this particle is - the importance of the argument is to isolate an absolutely singular entity.
Some might object: "What happens if all objects are infinitely divisible?"
The simple answer to that is that if this is the case, then no singular finite objects actually exist in reality.
Either they do or they don't. If they don't, then bang goes your reality of singular entities separated by spacetime. If they do, then let's proceed with the argument:-
What can we say about an absolutely singular entity?
An absolutely-singular entity must be indivisible. Clearly, if it was divisible, then it could not be classed as an absolutely-singular entity in the first place.
Therefore, an absolutely-singular entity is absolutely indivisible.
What can we say about absolute indivisibility?
Space and time are what are reported to exist between singular entities (thus separating those entities). But neither space nor time can separate something that is reported as absolutely-indivisible.
Consequently, an absolutely-indivisible entity must, IN itself, be spaceless and timeless.
Conclusion
You must now see where this is going: If an absolutely singular entity is spaceless and timeless in itself, then those entities are not 4-dimensional in themselves.
In a nutshell: no "singular thing" can truly exist as a 4-dimensional entity = there is no 4-dimensional reality.
4-dimensional reality negated.