Sunday, September 15, 2013

String theory and Mulla Sadra

Mulla Sadra is a notable Iranian philosopher, among whose concepts is one that is translated into English as "substantial motion". I do not have a scholar's precise understanding of the notion, but my rough understanding is that the previous notion of change in an entity was that its "accidents" might change but its essence would remain the same, whereas Sadra proposed that it could change in its being. Thus, rather than change just being motion through space, it could also take the form of change "within" a substance.

This reminds me of an elementary duality which appears early in the development of string theory. The string is a one-dimensional entity moving through an n-dimensional space. But it may also be conceived as a one-dimensional space in itself, with a number of fields existing within it. The values of these fields within the string, correspond to the position vectors of the points on the string, in the first picture. Thus this duality exchanges motion of the string through space, for substantial motion within the string. The second perspective is arguably the basis of perturbative string theory, which employs conformal field theory to describe the dynamics of fields within the string (worldsheet fields) corresponding to motion within a particular geometric background.

No comments:

Post a Comment