Four marks tell you when darkness, not stillness, has taken the wheel.

Read as a technical catalogue, each mark defined against the presence of its own cause.

Shankara names the four plainly: non-light, utter idleness, carelessness, and delusion, the signature of risen tamas. Madhusudana sharpens each into something closer to a proof: non-light persists even with instruction present, non-activity persists even with scriptural cause for action present and even understood, so that these marks cannot be explained away as anything but tamas. Read this way, the verse gives you a test rather than only a description, four failures that hold precisely where you would expect them not to.

Read as one inward collapse rather than four separate faults.

Ramanuja compresses the four marks into a single movement: knowledge fails to rise, the will stiffens, attention strays toward what should not be done, and seeing turns contrary. All four, on this reading, are one door leading the same direction, toward stupor, not four independent complaints needing four different remedies. For someone in active, devoted service, this collapse is worth watching for precisely because it would quietly hollow that service out from within.

Honest silence, with any extension clearly labeled as conditional.

No comment from Madhva survives for this verse, nor for the two verses immediately before it. Rather than construct a reading in his name where none exists, this space names that silence directly. What can honestly be offered is a labeled extension from his wider pattern: tamas as one insentient strand through which the Lord governs each soul's experience according to its own nature and karma, so these marks would be signs of that governance, not an independent power. This is extrapolation, not Madhva's own recorded word.

A thin surviving remark, honestly held as thin rather than expanded.

Abhinavagupta's fullest treatment of this stretch of verses sits at 14.11; for 14.13 what survives is only a brief echo of that comment, that the marks of darkness arise in turn just as the marks of passion arose in theirs. Nothing further is recorded in his own voice here. Any reading of these four as consciousness contracting into a denser self-forgetting is a conditional extension of his broader idiom, offered only as clearly labeled possibility, not as his stated word on this particular verse.

A terse, practical gloss meant to be used rather than expanded.

Sridhara's comment is brief and exact: non-light is lapsed discrimination, want of engagement is absent effort, carelessness is failed reflection on the moment's task, delusion is false fixation. He closes with a single memorable line meant to hold all three strands at once, sattva shines, rajas drives, tamas darkens, so a practitioner can recognize any of the three at a glance rather than only reason about them abstractly.

Read as a usable checklist for daily self-observation.

Carried into ordinary life, these definitions become a working test. Any unfitness that survives contact with its own remedy, understanding offered but not landing, a clear reason to act with no action following, an attention that misses the very thing in your hand, is tamas and not simple fatigue or a neutral pause. Naming it this precisely is itself useful, since a fog you can name is a fog you can begin to see through, where an unnamed dullness only deepens.