I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched C-beams glitter in the dark near the Tannhäuser Gate. All those moments will be lost in time, like tears in rain. Time to die.
Roy Batty (portrayed by Rutger Hauer) in Blade Runner
We are our experiences; when we're gone, they're gone. And so, we try to pass them on, but this is always inadequate.
Language only works if the people using it have enough shared experience for the words to effectively communicate the thought. If you try to explain an experience to another person, they have to have had the same or at least a similar experience in order to understand what you're talking about. As Wittgenstein points out, “if a lion could talk, we couldn't understand him” – this is because we don't have enough shared experiences with the lion to understand what a lion might be trying to communicate.
Imagine that you've seen God – how would you explain the experience to someone who hadn't? We can't even adequately explain the taste of ice cream, how can we explain seeing God? This is the primary problem for the mystic who tries to communicate the experience.
The handiest of the marks by which I classify a state of mind as mystical is negative. The subject of it immediately says that it defies expression, that no adequate report of its contents can be given in words. It follows from this that its quality must be directly experienced; it cannot be imparted or transferred to others. In this peculiarity mystical states are more like states of feeling than like states of intellect. No one can make clear to another who has never had a certain feeling, in what the quality or worth of it consists. One must have musical ears to know the value of a symphony; one must have been in love one's self to understand a lover's state of mind. Lacking the heart or ear, we cannot interpret the musician or the lover justly, and are even likely to consider him weak-minded or absurd. The mystic finds that most of us accord to his experiences an equally incompetent treatment.
William James, The Varieties of Religious Experience
I contend that most mystics never attempt to explain their experience or quickly give up trying. Thus, it seems to the general public that there aren't that many. Maybe you know one; maybe you are one.
According to the logic of Wittgenstein, Quantum Theory should be incomprehensible. It certainly doesn't fall under the category of "common experience". Yet, someone took a few observations and a repository of knowledge and philosophical inspiration and formalized it mathematically to the point that modern civilization works based on its technological applications.
The fathers of Quantum Theory, by the way, were all fans of Wittgenstein.
The thing about Quantum Theory is that many of its implications can be described as the Theory were a mystical revelation. There is the wave nature of everything, with localized particles appearing only when we interact with anything; there is non-locality and different states of being happening at once, although distinct, and let's not forget the Schrödinger's Cat.
Many scientists are irritated to no end that Quantum Theory is mystified, but that is where the mind naturally gravitates when faced with paradoxes of this nature. Scientists seek mathematical explanations in order to quantify a theory, so technology can come out of it.
Ancient Greek philosophers attempted to formalize mystical experiences with number and geometrical form. Indeed, they believed geometry and number were theurgy (divine work). Much earlier shamans took their version of knowledge and expressed it as myth. Entertainment value insured the knowledge would always be passed on, and encoded symbolism within the account would keep the intended information in the hands of those who could read it.
You don't need to go to some secret school, or find the secret book or teacher to crack that code. All you need to do is be initiated, which is jargon for having a mystical experience, which in Classical Greece meant to be given a hallucinogenic potion and partake in a ritual drama that you are then to keep to yourself.
The otherwise over-the-top events in a myth are viewed through a different filter, and the story becomes a comprehensive mystical narrative. Your initiation experience can be recalled, and meanings in the story will be clothed by the undeniable personal element. It just happens to be a cultural thing, so myths to the people holding them sacred, and to those who don't are very different accounts.
Some don't get mystical accounts, while others do. I believe this is in part due to mystical experiences we have in childhood that get swept under the subconscious rug. They are, nevertheless, latent memories of felt states that can self organize into a structure of adult understanding from someone else's mystical narrative.
The resistance of the normalized awareness state to mystical possibilities, the issues of belief systems supporting power structures in society, and the weight of a "burden of proof"- sensed by one who has had an experience as profaning it- are but a few factors that inhibit communication of one's own initiatory praxis.
The postmodern idea of Truth is unrealistic to me, and hypocritical in the face of the amount of funding going into the formulation of a Unified Theory of Everything. If existence IS, then there is Truth. Existence is the common experience underlying the common Truth.
To conclude this lengthy comment, the study of esoteric symbolism, archetypes and mythic structures of meaning can remind us of probable lost experiences from childhood. We need not remember anything specific. Just that there was a living element of presence in some of our experiences that we can revive the more we come in contact with mystical concepts that can also best be described in terms of allegory rather than a structuring of "facts".