Anyone ever wonder why we're in a universe of three spatial dimensions and one time dimension (3,1)? the following article gives the reasons why other possibilities are unlikely to contain observers:
1. more or less than one time dimension: insufficient predictability.
2. more than three space dimensions: insufficient stability.
3. less than three space dimensions: insufficient complexity.
http://www.hep.upenn.edu/~max/dimensions.pdf
At the end, the article doesn't rule out a (4,1) space completely. One would need to test out models of matter different from our matter, since "radical qualitative changes occur when n or m are altered".
to find out more about why the universe is the way it is beyond what this article says, do searches on the "anthropic principle".