What is this 'transcendent' and what is the way to knowledge of it? And why must it be so hard to find? Has anyone found it?
Well, this is the central problem, I think, Hassan. All we know is that it is. Who knows whether it can be found at all?
I think it is worthwhile trying to do so.
That is the cruel irony of life, the objective reality/tangible evidence is understood transiently.
I don't think you can dedicate your whole life to finding it, it would be another irony of life. Trying to understand it so much you spent little time living life.
This reminds me of a Zen Koan:-
""Before I studied Zen mountains were mountains and rivers were rivers; while I studied Zen mountains were not mountains and rivers were not rivers; when i finished studying Zen mountains were mountains and rivers were rivers.""
I suppose the idea is to know that the transcendent is living, just at a higher plane than other pursuits. Or, to put it another way, you are not wasting your life if you search for the truth no matter how stagnating it might feel. After all, as Rumi puts it way better than I ever have,
"What have you done with your life if you have not loved the absolute?"
As for tangible evidence - I think the only thing that matters is that you know with all your being that something is true. It does not matter how true something might seem intellectually or how much you may want to believe it, but unless you know it, with an absolute certainty that is beyond any dispute, a knowing that can never be doubted there is no use for evidence.