Spirituality is easiest to understand with practical, day-to-day physical analogies.
E.g., change of direction - inward vs. outward
Some other ideas are needed to flesh it out, though.
Attention is one. So is vantage point.
Putting these three together, one can define the spiritual journey as the journey resulting from changing the direction of one's attention from outward to inward with respect to the vantage point of one's body.
Subtle vs. gross does not quite fall as simply into a physical analogy, but Babuji gives a wonderful example - trying to use a crane to pick up a needle. The need to use something else - fingers - that are at the same or subtler level of dimension as the needle is immediately obvious. Yet, one's attention does not, and should not, get stuck at the level of "fingers." Regular practice for further subtilization to perceive much subtler objects and conditions and patterns is a must.
Per Daaji, Masters give or plant seeds internally. Such seeds have to be nurtured by spiritual practice for flowering and fruiting and further seeding to occur. Again, a physical analogy, but one that must be used carefully.
A similar physical analogy given is that of a planting a spark, which must become a flame and fire. And yet, Babuji prefers the final fire to be an electric one that gives intense heat without smoke. Here the analogy changes from organic growth to immediate manifestation!
And what does all this have to do with obtuseness?
Analogies are fine for an initial understanding of what is happening internally through regular practice. They must be discarded or forgotten after a point to avoid limiting, straitjacketing, or preventing the very real transmutation of inner attention, observing instruments, if you will, from gross to subtle, from crane-jaws to fingers.
Indian dārśanikas, aka philosophers, have given primacy to one's own dynamic experienc-ing over one's understanding or conceptual frameworks based on the continuing experiencing process called living. (The limited static physical analogy used is eating mangoes vs. talking about them.) One's own conceptual frameworks come second - along with activities for using, building, modifying, and destroying them. The least importance is given to the experiences, and reporting or conceptual frameworks, of others. This gives tremendous freedom and encouragement to a spiritual practitioner to trust herself, but frightens a nonpractising intellectual out of his wits.
Obtuse seekers imagine that they can reach great levels of subtlety simply by knowing or repeating terms that spiritual geniuses used to describe their experiences.
There are two immediate problem:
a) the terms are verbal reports of a subtle inner experience and inherently grosser than the experience itself, and
b) a report freezes a dynamic extended experienc-ing in time and space.
(In science, this is called sampling and is done many times over an extended period. Here, done just once.)
There is at least the saving grace in India that terms, especially Sanskrit ones like the mahavākyas, can be used as seeds for contemplation and may result in regeneration or replication of another's experienc-ing. This is however not guaranteed if the practitioner has stuffed his head with undigested commentaries and exegeses of such verbal reports. Letting go of conceptual straitjacketing is an absolute necessity for experienc-ing to occur.
Another simple and unfortunate example of obtuseness is lack of awareness of mental processes. There is no need to go to very subtle levels either.
A seeker who does not understand that "I" and "you" refer to physical bodies and objects in the outside world is going to have trouble reaching a level subtler than the physical. And if they compare, criticise, or even compliment others, they are still directionally challenged. They think they are looking and going inward, but their gaze is still frozen outward.
Relinquishing verbal descriptions and conceptual frameworks is absolutely necessary at very subtle levels, even if they were useful as encouragement initially. Such relinquishing happens naturally when the chattering emotional mind shuts down. Obtuse seekers, though, imagine that something has gone wrong!
There is a great deal of intelligence involved in spirituality, but it is not the usual intelligence that comes from intellectual wrangling. Instead it arises creatively and spontaneously, and even effortlessly, when the limited ego is relinquished. This relinquishing when it occurs naturally is true humility, not the artificial suppression or denial that obtuse seekers extol.
