The esoteric is opaque by definition; yet the depths rarely mind it when the surfaces discount them.
I subscribe to the notion that there are various levels to spiritual knowledge. As the alchemists put it: “as above, so below”— meaning, in a sense, that obvious facts correspond to inner truths.
For example: the leaves of a tree will brown with age and fall out. The same happens to the teeth of a man. These are, at a glance, entirely mundane facts. But on consideration (and with a pinch of poetic license) one could say that this speaks of how a person develops from a state of hunger and purity, and then moves to a state of decay and barrenness (the leaves being thought of as hungry for the sun, as teeth are for food). And in later life, a person returns to needing softer morsels, and all her showiness is stripped away, revealing the skeletal branches of her life’s choices.
In religion, too, there are levels of interpretation: the lowest being a blanket acceptance of the inherited laws. At a certain stage, the question arises: why? And what-for? There is a resistance to this leap from those who are content with the answer “because X said.” And here lies much of the “surface tension” between non-believers and believers—because experience of a self demands personal proof. Gurus and mystics arise to satisfy this demand, and due to the ambiguity of spiritual knowledge, many of the so-called wise are either willful charlatans, imbued with attractive charisma, or people who have received something personal, who try to communicate this to others. Some knowledge can be communicated in such a way that it is useful for others, and some knowledge can only be understood by personal revelation.
Esoteric knowledge (eso = inner), I believe, exists, but the exoteric (exo = outer) obscures it, and often corrupts, misinterprets, or outright discounts it.