[rms]

That's treating the 4th dimension as time, which is fine, but this article is referring specifically to the 4th spatial dimension. Sometimes pop physics type articles confusingly refer to the 4th spatial dimension as the 5th dimension.

[anigbrowl]

One might just as easily say that it's treating time as a 4th spatial dimension (offering a further 2 degrees of freedom, when our actual experience of time seems to be sadly one way, unless you read pravda). What he's suggesting is not substantively different from the color analogy.

[kschults]

What exactly is the 4th spacial dimension? Since we only experience space in three dimensions, how can we assign meaning to a fourth dimension in space?

[secret]

These may help visualize 4D space:

http://en.wikipedia.org/wiki/Fourth_dimension

http://www.instructables.com/id/How_to_draw_a_4_dimension_cu...

[rms]

The classic Flatland also helps. http://www.geom.uiuc.edu/~banchoff/Flatland/

[anigbrowl]

http://www.superliminal.com/cube/cube.htm