tatraivam sati kartaaramaatmaanam kevalam tu yaha |
pashyatyakritabuddhitvaanna sa pashyati durmatihi || 16 ||

This being the case, the one who has an untrained intellect, sees the pure self as the doer. Indeed, that person of perverted understanding sees not.
tatra evam sati : this being the case
kartaaram : doer
aatmaanam : self
kevalam : pure
tu : indeed
yaha : one who
pashyati : sees
akritabuddhitvaat : one with untrained intellect
na : not
saha : that person
pashyati : sees
durmatihi : perverted understanding
We look at the clouds moving in the sky, and we imagine that the moon is moving, though it is stationary. We see other vehicles moving and think that our vehicle, which is stationary, to be moving. The actions of one object can be superimposed on another object due to optical illusion. Shri Shankaraachaarya provides these examples in this commentary of this shloka to drive home the point that what we see or experience may not really be the truth.
Shri Krishna says that our entire life is steeped in the incorrect notion that we perform actions. With regards to the analogies taken up, the self is stationary, and Prakriti is moving. But we do not see this because our intellect is untrained. It is akrita buddhi. We have not imbibed the knowledge that action is performed by the five factors mentioned in the prior shlokas. The scriptures, and Shri Krishna, are repeatedly informing us that ultimately Ishvara’s Prakriti is performing all the actions, not our self, not the aatmaa, not the eternal essence. But we fail to see this. We are durmati, we have a perverted understanding.
Unless someone hears this statement from a teacher well versed in the scriptures, this ancient misunderstanding never comes up for questioning. The most common understanding is that the body is the self, the aatmaa. Some other people think that the jeeva, the individualized soul, is the aatmaa. But both these schools of thought attribute action to the aatmaa, which is incorrect. Furthermore, even the results of the actions go to the Prakriti. They do not go to the self, the aatmaa. The aatmaa is kevala, it is untainted, pure, and incapable of any change, modification or action. So then, what is the correct understanding? This is taken up next.