Ibn 'Arabi refers to The Reality, meaning (as far as I can tell) that God is objectively real and implying that our subjective states are just that - their reality is partial and dependent on something larger.
In our post-Enlightenment world we tend to view the world the other way up, as though our subjective beliefs were the touchstone of reality. We see, as St Paul says, 'through a glass darkly.' Or as Xenophanes has it, 'Only the gods see things as they are, but for us it is a woven web of guesses' (cited in Popper, The World of Parmenides). We are so habituated to seeing the world as it were upside-down that we take materialist explanations (chemical changes in the brain etc.) as more real than the experiences themselves. We think we are phenomenologists but our post-Enlightenment discourse is full of mechanistic hypothesis.
It is difficult to think outside the materialist paradigm. If we met something greater than ourselves we would reduce that to a chemical change in the brain, even though we know that experience forms and reforms the brain through neural plasticity. Causation works in both directions. Delusions and hallucinations occur, but not everything that we experience is illusory. Sometimes we don't know which way is up.
For this reason we don't understand Parmenides. His Way of Truth is his approach to reality, and his Way of Illusion (a reputedly large work now mostly lost) described what we would think of as science.
Does that mean we should abandon science? Assuredly not, because that which belongs in the material realm can correctly be dealt with by the methods of the material realm. Fantastical notions are still subject to appropriate demolition.
