68. Manifestly, therefore, the ignorance of God is not ignorance but a mystery: in the economy of His actions and words and manifestations, He does not know and at the same time He knows, or knows and at the same time does not know. But we must ask, whether it may not be through the Son’s infirmity that He knows not what the Father knows. He could perhaps read the thoughts of the human heart, because His stronger nature can unite itself with a weaker in all its movements, and by the force of its power, as it were, pass through and through the feeble nature. But a weaker nature is powerless to penetrate a stronger: light things may be penetrated by heavy, rare by dense, liquid by solid, but the heavy are impenetrable to the light, the dense to the rare, and the solid to the liquid: the strong are not exposed to the weak, but the weak are penetrated by the strong. Therefore, the heretics say, the Son knew not the thoughts of the Father, because, being Himself weak, He could not approach the more powerful and enter into Him, or pass through Him.