I asked this in another thread on this forum, and did not get an answer, so I decided to make a thread of it. Let me ask a question (phrased as mutiple questions)... Please temorarily disregard the "Is time/spacetime a spatial, temporal or neither dimesion?" argument for the sake of this question... What is the necessity of conceptualizing more than three spatial dimensions? Other than to fill in the blanks of the vairous unnecessary string (or brane) hypotheses (I really wish people would refrain from refrring to them as "Theories" being that not one of them can rightfully be considered a theory), interesting sci-fi plot-lines and pretty pictures, what is the purpose of it? What makes anyone think they exist? What valid evidence is there to support, or even suggest, them? (BTW, being a required integral aspect of incomplete conceptualized physics hypotheses does not count as valid evidence in my humble opinion) Is there any independant evidence for them? Simply... Why?