But the knowledge that is attached to a single action as if it were everything, without reason, not realizing the Self, and petty — that is said to be tāmasic.

Tāmasic knowledge: ekasmin kārye saktam — attached to a single action (body, pleasure, possession). Kṛtsna-vat — as if it were everything, the only reality.

Ahaitukam — without reason, irrational. Atattvārtha-vat — not conducive to the knowledge of truth (tattva). Alpam — small, petty, limited. It is knowledge that imprisons, not liberates.