Verse 18.21
पृथक्त्वेन तु यज्ज्ञानं नानाभावान्पृथग्विधान् । वेत्ति सर्वेषु भूतेषु तज्ज्ञानं विद्धि राजसम् ॥ १८....
किंतु जो ज्ञान अर्थात् जिस ज्ञान के द्वारा मनुष्य सम्पूर्ण भूतों में भिन्न-भिन्न प्रकार के नाना भावों को अलग-अलग जानता है, उस ज्ञान को तू राजस जान ।
However, Partha, if one can only see the multitude of things in this world in terms of their limitations and divisions, then this being possesses  the impure knowledge of the Rajas mode of nature. (This passionately natured person possesses knowledge that is derived from many theories, teachings, mental logic, and speculation that exist in this world).