एवमेव खलु सोम्यान्नस्याश्यमानस्य योऽणिमा स उर्ध्वः समुदीषति तन्मनो भवति ॥ ६.६.२ ॥
In plain words
Just so, my dear, of food that is eaten, the finest part rises upward and becomes mind.
The commentators
Chāndogyopaniṣadbhāṣyam· bhāṣya
यथा अयं दृष्टान्तः, एवमेव खलु सोम्य अन्नस्य ओदनादेः अश्यमानस्य भुज्यमानस्य औदर्येणाग्निना वायुसहितेन खजे- नेव मथ्यमानस्य योऽणिमा स ऊर्ध्वः समुदीषति ; तन्मनो भवति, मनोवयवैः सह संभूय मन उपचिनोतीत्येतत् ॥
In plain words
Just as in this familiar example, O gentle one: when food is eaten and digested by the digestive fire in the belly—churned by the vital breath just as curds are churned with a churning stick—whatever subtle essence rises upward becomes the mind. Joining with other mental elements, it nourishes and builds up the mind.
Close to the Sanskrit
Just as this example: even so indeed, O gentle one, of food such as rice being eaten and enjoyed, churned by the gastric fire accompanied by wind like a churning stick, whichever subtle essence rises upward, that becomes the mind; uniting together with mental parts, it builds up the mind—this is it.