How do we know that the universe is three dimensional?

  • Context: Graduate 
  • Thread starter Thread starter Fiziqs
  • Start date Start date
  • Tags Tags
    Universe
Click For Summary

Discussion Overview

The discussion explores the nature of dimensionality in the universe, questioning how we ascertain that our experience of reality is three-dimensional. Participants consider sensory perception, theoretical frameworks, and the implications of different dimensional models.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that our three-dimensional perception may be limited by our sensory input and cognitive interpretation, raising the possibility of additional dimensions that we cannot perceive.
  • Others highlight the difference between two-dimensional representations, such as photographs, and the actual three-dimensional experience of space, emphasizing the limitations of visual cues.
  • Parallax is mentioned as a factor that contributes to our perception of depth and dimensionality.
  • One participant references string theory, which posits the existence of ten or more dimensions, but notes the lack of evidence for these extra dimensions compared to the evidence supporting three spatial dimensions.
  • Holographic theory is introduced, suggesting a potential two-dimensional nature of reality, though it is noted that the theory lacks detailed development.
  • Questions are raised about the dimensionality of holograms, with some participants proposing that interference patterns could exist in higher dimensions and that these patterns can be observed in three-dimensional space.

Areas of Agreement / Disagreement

Participants express a range of views on the nature of dimensions, with no consensus reached. Some argue for the established perception of three dimensions based on sensory experience, while others propose alternative models and theories that suggest different dimensional frameworks.

Contextual Notes

Participants acknowledge the limitations of current understanding and the dependence on sensory perception and theoretical models. The discussion reflects unresolved questions about the nature of dimensions and the evidence supporting various claims.

Fiziqs
Messages
134
Reaction score
0
When we look at the world around us our minds create a three dimensional representation of the world based upon our sensory input, but how do we know that there aren't in fact more dimensions from which we either receive no sensory input, or from which we receive input, but our brains and our mathematics have evolved to interpret three dimensionally? Or perhaps there are only two dimensions, from which our minds extrapolate three dimensions. Or taken to the extreme, how do we know that there are any actual dimensions at all?

How do we know that what we see and interpret as being three dimensional, actually is?
 
Space news on Phys.org
Fiziqs said:
How do we know that what we see and interpret as being three dimensional, actually is?

think about the difference between a 2 dimensional photo of a room and the real 3 dimensionality of that room
think about what you can and cannot do in the photo Vs in the actual room

consider depth of field implied and real
 
And consider parallax.
 
If you follow any popular modern science, you'll hear about how string theory predicts 10 or more space dimensions, and we can't see these dimensions because they are small and curled up. But there's no evidence for extra dimensions and there's plenty of evidence for 3 (space) dimensions.
On the other hand, you'll hear about holographic theory which suggests that there might only be two dimensions, but none of the details are worked out, so it can't really be called a theory.
Ultimately, science is about experiment, and all our experiences seem to show us a 3D universe, so unless we can come up with better experiments which show the contrary, we should go along with the preponderance of evidence and our intuition and simply accept 3D. "know" is too strong a word here.
 
  • Like
Likes   Reactions: Thewindyfan
Are holograms necessarily 2D? I can envision interference patterns in higher dimessions.
 
anorlunda said:
Are holograms necessarily 2D? I can envision interference patterns in higher dimessions.
In fact, all (near field) interference patterns are 3D. It's just that we normally observe them by putting a screen (2D) in the way.
The interference pattern that's produced by an rf transmitting array over a hilly terrain is demonstrably 3D because the maxes and mins vary as the receiver is moved in 3D. It would be possible to have a photographic or electronic light sensing array that extends in 3D as long as the receptor cells were very small.
 

Similar threads

  • · Replies 22 ·
Replies
22
Views
4K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
18
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 33 ·
2
Replies
33
Views
8K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
5K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 8 ·
Replies
8
Views
6K