Edit: It’s makrooh, NOT haram, to sell something when you’re 50%+ sure it’ll be used for haram.
In Islamic finance, permissibility to sell something is tempered by the certainty principle–that is, how certain are you that this thing you’re selling will be used properly?
Say you sell grapes in a specialty grape-only store. A few types of customers come in:
- A young woman comes in with her little boy and buys some grapes; you see her feeding him the grapes as soon as the cashier scans it through. Is it permissible to sell her grapes? Absolutely. It’s halal.
- A young executive comes in; you see “Wines R Us” embroidered on his jacket. He asks you, the owner, about the quality of different grapes you sell, and mentions that he needs sour grapes for a certain type of wine. Is it permissible to sell him the grapes? Absolutely not. It’s haram. Because it becomes the means of haram.
A man comes in looking to buy grapes. You think that he might be making wine with it. But you’re not sure. What’s the ruling? It depends on how certain you are.
What’s the proof of this principle? The hadith in Bukhari. A man came and asked the Prophet (صلى الله عليه و سلم), what do I do if I think I broke my wudoo? The Prophet (صلى الله عليه و سلم) said, if you hear it or smell it, THEN act on it.
Is it possible you broke it, but without noise or maybe without smell? Yes! There’s a possibility! But are you required to act on that possibility? No! Because it’s less than 50%–until the signs of certainty appear to you!
Another proof is ahaad hadith (a hadith where, in the chain, at some point, there’s only one person narrating the hadith). Is it possible, in this case, that the one person made a mistake in the hadith? Yes. How possible is it–given the strict requirement of Saheeh Bukhari and the science of hadith? Very, very small; less than 1%. It’s not 100% certain that the hadith is correct–but you are obliged to act as if it is certain.
So think about it. This applies to everything from selling iPods (where the majority are used for haram–music) to grapes (which may be ok or maybe not) to umbrellas.
Wallahu ta’ala ‘alam.
Shaykh Tawfique Chaudhry. The Real Deal. University of Toronto, Toronto. 08 Jan. 2009.