I am not a philosopher – far from it, but in discussions it is frequently asked how a person can know that an experience of the sacred Transcendent is really genuine.
I can only reply that it can be known in a similar manner as to how it is known when we are having a headache, a personal insight, and/or prefer (say) the good, the true, the beautiful over the sordid, false, and ugly. No “mechanism” is called for, beyond having the experience – “having the knowledge” – itself. I don’t believe that I need to submit myself to an fMRI scan or a neurologist’s examination to tell me what I’m experiencing, or if the experience is “real”. Basically, such critical inquiries are really asking how I “prove to myself” that the experience is “divine” – a quite legitimate query, of course. “The proof”, as the cliche’ goes, is “in the [eating of)] the pudding”.
The divine signature comes in various forms. For me it has primarily been the emergence of an intra-psychic (psychic = mental or “soulish”, not “Woo”) quality, which I know for a fact that I cannot myself generate. It comes as a gift from a sacred, Transcendent agency that is clearly real, but is definitely not my ego, and is not psychoanalysis’s “unconscious mind”. The experience is ineffable, “Other”, and ego-dystonic (even as it is comforting and illuminating). I know that “I” am not creating it. Something else is. In my own tradition it is called “a raft from the Other Shore” (or “Shinjin“), which well-describes and specifies its “alien” origin and nature.
The kind of specialized religious language that identifies and classifies such experiences is simply the best we can design in order to make mystical participation somewhat expressible in human language. The classification need only be “good enough”. It cannot be perfect. It identifies certain traits and parameters of the experience and supplies a limited nomenclature for it.
Suppose I was a curious person living, say, 175 years ago, and an explorer told me of a then-unfamiliar animal that had been seen on the African planes, an animal that looks almost identical to a horse, except that it is covered in black and white stripes, and it is called a “Zebra”. I then manage to travel to Africa and I see a herd of “black and white-striped horses”, and the term “Zebras!” comes to mind. That term is the “good enough” descriptor for labeling the unfamiliar animals. Similarly with experiences of transcendence, which the mystical traditions have ornamented with their own good enough descriptors.
Labels exist, descriptors exist, and are available to apply to various states claimed in the experience of divine transcendence. The labels won’t be perfect, but they will be pragmatically meaningful, and helpful precisely because they assist in translating the experience into always-inadequate human terms. The transcendental experience has certain observable, “black and white stripes” that identify it, and a spiritual lexicon exists that aids in pragmatically labeling any particular mystical “Zebra” that one happens to be observing – or even to be “riding”.
In my own experience of Jodo Shinshu/Shin Buddhism, Shinjin is defined as a gift from Amida Buddha – a gift of perfect faith – which we ourselves are unable to produce. The Buddha produces it for us, and within us. For me, this is proof-positive that Amida Buddha is the sacred, Transcendent agency that is moving and working within me to create in me the state and the capacity of perfect faith. The “proof” is in the experience of having something, of realizing and knowing something, that is “in” me, but not “of” me. This is sacred Transcendence realized in this very life through reception of a gift from the transcendent Source called in Jodo Shinshu, Amida Buddha.