The Citadel of the Mind

The stoic philosophers referred to the ‘soul’ as the thing which receives sensory impressions from the outside world. They call sensations or impressions ‘phantasia’. By nature, the soul is sensitive to receiving sensation, and this is a process of the physical world. At the same time, a sensation of some object replaces the real object, since sensation is a change in the soul. Whether sensation is solely a process of the world impacting the soul, or a change in the soul, sensation is nevertheless a process of nature or the physical universe.

But they also make reference to a part of ourselves that is sovereign, above sensation, and the source of true freedom. This is our inner discourse, or interpretation, that we have about the objects that we sense and that appear in the mind. It is the guiding part of the soul.

The stoics bring about a boundary between sensation and this sovereign or guiding part of the mind. There is a ‘citadel of the mind’ that sensation cannot bridge, since our interpretation of whatever we perceive is open to amendment and alteration by the self.

References:

Marcus Aurelius, Meditations