This potential gas-bag wonders if he dares join in this discussion...I've studied aspects of practical philosophy for many years, but only in the last five have given any attention to poetry. However the two have inevitably come together in practice. That doesn't mean I can verbalise this effectively...
Since the Hindus have explored and analysed and formulated the movements of mind more effectively (imho) than the West and for longer, their findings/theories are particularly interesting to creative artists.
The theories I've found particularly interesting to consider recently are primarily, that 'as without, so within' - in other words, that whatever is in the 'outer world' as we view it, all the cosmic forces we observe, are all present in the inner world. This is the greatest justification for poetry - that unique activity which brings these worlds together with mind and heart. I'm sure that every poet really believes this.
The second which I've only come across recently (and the forever forthcoming Hindu Encyclopaedia will only scratch the surface of this) is that every 'action' as we see it, is only a 'reaction' to events outside or inside or both. So poetic stimulus can easily be seen to work like this; and obviously, from the lost 'external', Bukowski if you like, situations, or the more internal, as Wordsworth. Correspondingly, with this constant turmoil which is our mind, some poets are more 'reactive'; some more 'contemplative'; some brilliantly using the two together.
Surrealism was one great recent experiment, a partial success, to access these deeper levels of our own(universal) mind - every poet knows those ideas, images, heavenly lines of poetry, which seem to 'write themselves'.
And here is a fascinating theory I've only just come across: that the 'unified' mind, stirring out of stillness, makes a primary division in two almost simultaneous directions: extreme polarity (that is, comprehending the most extreme opposites, love-hate, joy-sadness, etc, as the parameters of the mental and emotional world) and duality - the constant division of any aspect of unity into first two, then into continual diversity, fragmenting our minds into, ultimately, the most trivial mental activities which just reduce our great into a tiny one. And the only antidote to this is some form of 'tranquillity' as with Wordsworth's personal search for this - which brings the mind back to unity. And of course this doesn't mean 'not thinking' but keeping all the senses continually open, rather than walking through the daffodils unnoticing, churning over one's own or the world's problems!
I'd better stop there...sorry for any typing mistakes, head-hand coordination not so good these days.