No American architect of his generation has probed deeper into the philosophical roots of historical change.

The approach was almost entirely academic, with far more debate about the philosophical roots of Beauvoir's work than about her impact on feminist politics.

Its philosophical roots are in the Cartesian revolution.

One has an apparently right-wing orientation, the other is apparently left-wing, but they both have the same philosophical roots.

However, they share historical and philosophical roots in Christian pacifism.

They have paid attention to the academic, moral and philosophical roots of the movement.

This, too, has philosophical and historical roots.

This points to the critical philosophical roots of this approach.

Furthermore, he explains how each of these shared a single cultural and philosophical root, though occurring in different times and locations.

The philosophical roots of agrarianism include European and Chinese philosophers.