The view prominent in Hegel that ideas or concepts can be seen as historical forces, having actual effects in the real world. It is not entirely clear what level of realism this suggests. Hegel writes that ‘This concrete had manifold forms; social instincts in the practical sphere, laws of nature in the theoretical’ (Lectures on the Philosophy of History), suggesting something like a physical reality to the universal; a less demanding doctrine would simply stress the operation of ideas like that of equality, or those of reason and freedom, on the minds of people and hence on actions and historical developments.