Peter Aspden on artistic truth:

Picasso's "Guernica" - played with the idea depicting a face so racked with pain that it seems physically to fall apart on the canvas.

During his country's civil war, he was quick to translate the sense of exhausted anarchy into a remarkable image.

Resulting from the discomfiting battle unfolding inside him because of his three lovers, were the extraordinary studies of weeping women; desolate images of anguish that capture with violent veracity the primal sense of breakdown that occurs when our emotions are wrenched beyond control.

More current work skims surfaces. It skates rather than plunges. It fulfills easy ambitions instead of setting itself impossible tasks.

The celebration of simulation and ambiguity has replaced the near-murderous drive to arrive at a moment of artistic truth.