On Light

‘Truth is sought for its own sake… Finding it is very difficult
and the road to it is rough. For truths are plunged in obscurity.’

– Alhazen (965CE/354AH –1040CE/430AH), Doubts Concerning Ptolemy

Ibn al-Haytham, known to all as Alhazen,
sits in his chair looking at the window
opposite him, the rectangle of light revealing
the jasmine tree in his small garden, finally in blossom.

He’s been under house arrest for ten years
this window and its light particularly
familiar to him. He had once promised
the sixth Fatimid caliphate and their Caliph,

Al Hakim, that he could regulate the floodwaters
of the Great Nile by means of a dam. Al Hakim
believed him and gave him everything he needed
both in terms of materials and men, yet even the great

Alhazen soon recognised that it was a doomed
plan and feigned insanity of mind and purpose
there in the heat of the delta, to have his life
spared as the water flowed by him, unstoppable.

And thus he sits here in his chair opposite
a window he knows too well. Yet when he looks
at it he doesn’t feel regret or anger
for the years lost in this room; no, for Alhazen

has used this time well, conducting many
experiments on the nature of light, the daylight
from this window the only source he needed.
Here he has written his masterpiece on optics

outlining research and offering experimental proofs
on refraction, reflection, spherical aberration,
parabolic mirrors and the magnifying power of lens.
Yet, one experiment stands above them all,

evidence to overthrow a millennium of opinion.
He had simply placed a thick, black fabric
across the window and secured it tightly, then made
a small aperture at its centre, the rooftops

and mosques of the city suddenly projected
upside down on the wall opposite, showing
for certain that light travels from an object
to our eyes in straight lines and by no other means…

Alhazen, though, feels different today.
He has just heard of the Caliph’s death
and with that news he is free to leave this enclosure.
So he sits in his chair looking at this window

for the final time, nostalgic for all it has
given him. He stands at last and turns to the door.
He thinks he might like to go to the market
and buy fresh pomegranates.


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