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I came up with this line somewhere:

To properly experience $n$ dimensions the retina of the organism should be at least of $n-1$ dimensions.

And human eye has $2$ dimensional retina, so we can experience at most 3 dimensions properly.

Now my question is:

  1. Do more than 3 dimensions exist?

  2. What is the proof that 'there exist only 3' or 'more dimensions do exist'?


marked as duplicate by John Rennie, user36790, Danu, RedGrittyBrick, Kyle Kanos Nov 27 '15 at 11:19

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  • 3
    $\begingroup$ Unrelated to dimensions, but multiple instances of "do" in your title do exist. $\endgroup$ – Marc van Leeuwen Nov 27 '15 at 9:18
  • $\begingroup$ I doubt this assertion. Our 2-dimensional retina can by no means observe the third dimension, as is demonstrated with lots of optical illusions. We only have a 2-dimensional projection to work with which can be the result of an infinite number of 3-dimensional arrangements. With two eyes/retinas the situation is different but one could argue that the resulting overall optical system is actually 3-dimensional. $\endgroup$ – Peter A. Schneider Nov 27 '15 at 10:54
  • $\begingroup$ On the contrary I would contend that in order to fully observe 3-dimensional objects including their insides one needs an 4-dimensional retina, or at least one with 3 dimensions of which one is orthogonal to the dimensions of the object. We as 3-D beings can fully grok a surface, but another surface in the same plane as the observed one could not. Same with 3 dimensions. In order to look inside a body you need another dimension. $\endgroup$ – Peter A. Schneider Nov 27 '15 at 10:58
  • $\begingroup$ It's interesting to note that jumpings spiders have several retina layers, so the are three-dimensional. $\endgroup$ – jinawee Nov 27 '15 at 12:49

Well, I suppose we could add time as a 4th. However, apart from that there is no experimental evidence whatsoever for more than 3 spacial dimensions. String Theory and its friends remain theories with negligible experimental evidence in their favor.

  • $\begingroup$ Well this makes me feel, whats that thing which travels along this dimension $\endgroup$ – Display name Nov 27 '15 at 8:09
  • $\begingroup$ And if time is considered the 4th dimension, then the retina is actually 3-dimensional, and indeed we can observe 3-dimensional objects traveling through time, with us ;-). $\endgroup$ – Peter A. Schneider Nov 27 '15 at 10:50

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