Everything we see is the creation of the mind. . . hence, a perception, but a strong one at that. There are a few poems prior to this which talks about how if one has to know something, he has to experience it himself in first hand and when he does that, is unique to the individual. He can put it in many words and make it relatable to others, but all he is doing is creating another perception, a shadow of the reality.
There is no difference between swapna and jagrat . . . even psychologists have found it to be true and suggest a technique to improve things in the real world after playing it out in the mind. In some case even treat some disorders. However, the definition of mind is made very simple. (మనస్సు, मन vs mind).
If you take another extension to the above two lines with the same loose meaning of word mind and apply it to every physical ritual of religion, one could see that it is an attempt to bring about change in mind. It is either to create a strong remembrance or reconcile a few things in mind and lead to memories audit trail. The same with poojas or rituals related to prayaschitam (repentance), all of them are for mind.
So, what if one can master the mind ?
This amazing keerthana of Thyagaraja says it all.