Question: If the universal Atman Self were the natural form of the Self, and the localized individual egoistic self were something superimposed, then the natural form ought to be more apparent.
In Nature, the basic form is frequently seen, and the unusual form, being relatively unnatural, is rare. For instance carbon does not often appear as diamond but is seen everywhere as charcoal and graphite. Atman would correspond to the diamond, as it were, an exceptional crystal structure, and therefore rarely seen. Is it not the case that Atman too is rarely experienced because it is an exceptional form?
Answer: The assumption that the basic form is the one commonly experienced is unjustified.
Consider the case of one of the commonest elements, seen everywhere: water. Its structure is two hydrogen atoms in a boomerang shape, with an oxygen atom at the angle. Now why is it not a gas? Much heavier molecules, such as CO2 are gases, so water too should be a gas.
The answer is that water is a gas, and water vapour is its natural form. It appears as a liquid because the molecules are held together, by processes even now not completely understood. It is truly a gas, and when left alone it evaporates and resumes its pure, fundamental form.
So the Self is truly Atman, and when it is purified and then left alone in stillness of meditation, it resumes its natural expansion to universality.