(Tap or hover over green words for translation.)
The word 'bodha' means knowledge or recognition, so it has to take place in the mind, not elsewhere. Ātmā is always present and it is always the same, one and non-dual whether you know it or not—like even a sugar crystal is sweet whether it knows it or not. Ātmā is everything and at the same time it is free from everything. Ignorance of this fact has to go. Ignorance is removed only by knowledge. The ignorance of a pot is removed by the knowledge of the pot alone. For the knowledge you have to employ the appropriate pramāṇa, means of knowledge.
The śāstra has the status of a pramāṇa because it removes the wrong notions I have about ātmā.
Ātmā, by nature, is param brahma and that param brahma is not known to us. The pramāṇas available to us are only good for knowing things other than ourselves. This ātmā is already svataḥ-siddha and it is this svataḥ-siddha-ātmā that is mistaken for an individual, a jīva, a doer, a kartā, an enjoyer, a bhoktā, one who is happy one moment and sad the next, a sukhī and a duḥkhī. That I am a jīva, an individual, means that I am someone who is limited, as good as the body, etc. This is the natural conclusion of every jīva because of ignorance, avidyā.
The status of being a jīva, jīvatva, has been superimposed upon the ātmā. In other words, the seeking person is born of avidyā. This is an error of self-identity, which only the śāstra can resolve. One's own pramāṇas are of no use here. The śāstra does not prove the existence of the ātmā, it only removes the confusion. For this reason, it has the status of being a pramāṇa, i.e., it has pramāṇatva. It does not bring to your recognition the ātmā as an object that is totally unknown, as it does for other unknown things like heaven, for instance.
When the śāstra says there is a heaven, heaven as an unknown thing is brought to your understanding. You understand that there is such a thing as heaven. When the śāstra says that this particular ritual will produce this particular result, it is definitely bringing an unknown thing to your recognition. That this ritual has this efficacy is not known to you by any other pramāṇa. Therefore, the śāstra has the status of being a pramāṇa by bringing to your recognition something that is totally unknown to you and that cannot be known by you through any other pramāṇa.