Bhagavad Gita, Chapter 14, Verse 18

The Sattva-abiding go upwards; the Râjasika dwell in the middle; and the Tâmasika, abiding in the function of the lowest Guna, go downwards.

A real, spatial image is used here, rising, staying level, or sinking, to describe where each path actually leads.

Krishna gives the three modes a genuine trajectory rather than treating them as equally neutral options. Real direction, not just real difference, separates them.