  The implications of string theory for understanding the dimension of
uncompactified spacetime are investigated. Using recent ideas in string
cosmology, a new model is proposed to explain why three spatial dimensions grew
large. Unlike the original work of Brandenberger and Vafa, this paradigm uses
the theory of random walks. A computer model is developed to test the
implications of this new approach. It is found that a four-dimensional
spacetime can be explained by the proper choice of initial conditions.
