I have been thinking about that quote a lot since this thread started. Very interesting guy, writing at an amazing period of history. He's writing at the height of medieval Islamic science and innovation. I've never studied him, but I know a bit about the people he's writing about and he's not the only one in his day to seek a path away from "truths" that are not immune from error. There are tremendous parallels between his time and ours. I think the translation is a bit unfortunate, perhaps. There was a time there when Islamic writings were translated very aggressively into English (it's a long history). Basically, the translation lost the poetry of the writing and made it seem like an aggressive, war-like language. Take this line:
to make himself an enemy of all that he reads, and, applying his mind to the core and margins of its content, attack it from every side
I don't speak Arabic, but from what I know of the time period and the culture, I bet there are ways of translating this that are less confrontational. "enemy" "attack" These aren't gentle words conducive to gentle conversation.
The feeling I get from that quote is that the author is making the same fallacy he's trying to prevent. He recognises that once we have "truths", it closes our minds off to other possibilities. There may very well be a truth to the universe, but looking at history, human understanding of this 'truth' seems to me a moveable feast. Yet, he wants to open his mind from one way of thinking and close it by finding a different way of thinking.
Why doesn't this quote fit with permies?
The aggressive language is a big problem. "Enemy," "critical," and "attack" are emotionally heavy words that encourage confrontation.
The drive to get at the "truth". Permies isn't about 'truth'. It's about exploring new ideas. There are so many "truths" that are presented to us, that turn out to be untrue with closer examination. Like your guy ibn al-Haytham says, we can't trust truths. "the truths...are immersed in uncertainties [and] not immune from error..." This bit fits with the atmosphere of permies. The rest, less so. "if learning the truth is his goal..." implies pursuing the truth should be a person's goal. Doesn't that contradict what he just said about truths being uncertainties?
What is "true" for one situation isn't for another.
Think about it like building a house.
Maybe we study up on all the different ways we can build a house. We disbelieve the modern-day way of building houses is the best ("make himself an enemy of all that he reads"), look at all the different ways of building houses ("applying his mind to the core and margins of its content"), evaluate each method ("attack it from every side."), we've consulted other people with different backgrounds ("also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency"), and arrive at the truth that
cob housing is the best kind of housing.
Cob may not be the best kind of housing, but it's easy to spell, so I'll use it for this thought experiment.
For truth to be truth, it must be universally applicable. So, if it is true that cob is the best thing for building houses, then it must be the best thing for everyone to build a house from.
Only, when we get to the building site, maybe there is no clay. Maybe we build the best cob house to the best specifications, and the weather in that location is wrong. Maybe we need temporary housing for three months. Cob does not strike me as temporary. Maybe we need moveable housing. Maybe there is a weight limit for some weird reason. I suspect there are lots of things that could make cob construction not work in different situations.
Permaculture, as I understand it, is about designing systems that work in different locations. When we think we know the truth, we close our mind to other possibilities like maybe there are other natural building styles that might work better than cob.
So at permies, we avoid talking about 'truths' and talk instead about opportunities, options, experiences.
Think of this place more as a brainstorming session. We have a challenge and we come here for ideas and inspiration.