Who created the concepts of Atman and Brahman?

God created all concepts in existence. Later, the concepts that originate in God have become subject to human interpretations and speculations.

Real knowledge is knowledge from God that has been passed down to humanity via the disciplic succession. That’s why we need a spiritual master to teach us knowledge of the world, as it is, as opposed to knowledge of the world, as we think it is.

So knowledge from God is revealed to us by the descending process of knowledge, where as human, speculative knowledge is called ascending knowledge. So real knowledge, which means absolute knowledge, is deductive knowledge, and the relative knowledge of humans is inductive knowledge.

Deductive knowledge is shabda pramana, meaning knowledge received from higher authority. And inductive knowledge is knowledge received from the mind, IOW, it is speculative knowledge.

I know I’m guilty of it myself, but Srila Prabhupada used to say, if you start a sentence with ‘I think’ you should go into a cupboard and finish it. Seriously, who gives a hoot what we think? Everything we say should be backed by sastric evidence.

Krishna says:

Just try to learn the truth by approaching a spiritual master. Inquire from him submissively and render service unto him. The self-realized souls can impart knowledge unto you because they have seen the truth.

Having obtained real knowledge from a self-realized soul, you will never fall again into such illusion, for by this knowledge you will see that all living beings are but part of the Supreme, or, in other words, that they are Mine.

Even if you are considered to be the most sinful of all sinners, when you are situated in the boat of transcendental knowledge you will be able to cross over the ocean of miseries.

As a blazing fire turns firewood to ashes, O Arjuna, so does the fire of knowledge burn to ashes all reactions to material activities.

In this world, there is nothing so sublime and pure as transcendental knowledge. Such knowledge is the mature fruit of all mysticism. And one who has become accomplished in the practice of devotional service enjoys this knowledge within himself in due course of time.

A faithful man who is dedicated to transcendental knowledge and who subdues his senses is eligible to achieve such knowledge, and having achieved it he quickly attains the supreme spiritual peace.

But ignorant and faithless persons who doubt the revealed scriptures do not attain God consciousness; they fall down. For the doubting soul there is happiness neither in this world nor in the next.

—Bhagavad-gita, 4.34-40