Krishna: What do you already know?
Arjuna: I know the dictionary meanings. The term prakṛti means “energy – the thing from which other things are created.” The term puruṣa means “person – the conscious being.” So, prakṛti is matter, and puruṣa is spirit.
Krishna: Good. Do you know anything else?
Arjuna: I think that matter is the field-of-activity, and spirit is the field-knower.
Krishna: Good. Then, what confuses you about them?
Arjuna: How and when do the two become related?
Krishna: You must understand that matter and spirit are both without chronological origins. Their relationship has no beginning.
Arjuna: How can matter be eternal? It is constantly being created and destroyed!
Krishna: Exactly. Matter has delimitations, and is therefore in an eternal state of change.
Arjuna: Spirit has no changes?
Krishna: Not directly. Not in the same way that matter does. We say that matter causes the mechanisms and substances of creation. By identifying with these fluctuating substances, spirit experiences a sensation of change. Therefore we say that spirit causes participation in emotions like pleasures and pains.
Arjuna: How do the two become linked together?
Krishna: Spirit becomes enmeshed in matter because it wants to enjoy the various things available in the field. That is why spirit embraces qualification and delimitation, and takes birth in matter through various wombs.