Abdul Hadi Badi-al-Zamar, a Sufi, set off at dawn to climb a mountain. He left his trust steed, Aqil, tethered with food and water and set out as the sun peeped over the horizon.
He enjoyed the journey, following the single pilgrim path as it mounted past the Tomb of the Saint, and through the grove of beach trees, skirting the Lake of Tranquility, where he sat and ate his simple lunch, drinking from the lake’s healing waters. He slept for a bit and then continued up, climbing the steps hewn into the rock-face, and stopping briefly to admire the view from the Great Cave with its wonderful frescoes of geometric designs. After reaching the top of the cliff he scrambled up the rock and stone strewn path till he reached the summit, exactly as the sun set.
He decided to spend the night on the mountain summit, meditating beneath the stars. This he did.
Abdul Hadi rose while it was stll dark, did his ablutions, and started his descent just as the sun peaked over the horizon. Again, during his descent, he stopped at various places, including the Buddhist Stupa, where he prayed briefly, the High Meadow, with its lovely mountain flowers, and once more, the Tomb of the Saint.
He reached the bottom of the mountain just at the moment the sun set.
The Sufi smiled to himself when greeted by one of his disciples. He explained that his journey up and his journey down the mountain had taken exactly the same time. The path was one, and he had never left it.
“Can you prove,” he asked his disciple, “that therehasto be one place, somewhere between the bottom and the top, where I was at exactly the same time of day, on the way up and the way down?”
His disciple thought for a moment, and then said, “No, it is not possible to prove that.”
“Think again,” said the Sufi, “it is certainly possible. It can be shown incontravertibly. What you or I cannot be sure of is where. But that it occurred there is no doubt.”
The next day the disciple was very excited and said, “Yes. I can prove it.”
This problem was first posed by Arthur Koestler in his book, The Act of Creation.