  Some shortcomings in regard to our lack of conceptual understanding of string
theory are displayed and prescription to untangle them is proposed. String
theory should be a fundamental dynamics of four dimensional symmetric
space-times. Properties of the two dimensional equivalent action are studied,
in the hydrodynamic approximation. In the pressureless regime it is conformal
invariant. Correlation of our proposal to 't Hooft work on quantization of
black holes[7] and work on 2D black hole solutions established by Witten [14]
are pointed out as perspectives of the present work.
