Technically you need the extra dimensions. At first people didn't like them too much, but they've got a big benefit, which is that the ability of string theory to describe all the elementary particles and their forces along with gravity depends on using the extra dimensions.
-- Edward Witten
   
Edward Witten   Name:
Edward Witten
Type:
Mathematician
Nationality:
American
Birth:
August 26, 1951
https://www.nutquote.com/quote/Edward_Witten