Full Idea
Some philosophers hold that the soul is in its essence light.
Gist of Idea
Some philosophers say the soul is light
Source
Plutarch (75: Is 'Live Unknown' a Wise Precept? [c.85], §6)
Book Reference
Plutarch: 'Selected Essays and Dialogues', ed/tr. Russell,Donald [OUP 1993], p.123
A Reaction
A nice idea, to rival the stoic view that the soul is fire. It is understandable to propose that the soul is some sort of lightweight and fast moving matter. How else could thought be achieved physically? Nowadays, parallel processing is our only model.