The common perception that two women are required in the place of one male witness is overstated, although this had been a widely attested presupposition in Islamic Law. But this presupposition causes difficulties to the modern Muslim mind, since our present experience is that women are equal competitors with men in most fields, and that they even excel over men in some fields. This experience (and the accompanying doubt that arises due to it) calls for a revaluation of the question.
The fact is that in the Quran the only mention of something like this is in the case of a loan transaction (Quran 2:282). But even there, the point seems to be that one woman will attest, and the other will remind her in case she slips in her testimony. The scholars tended to generalize from this and say that we need two women witnesses in the place of one male witness.
But there is a case in the Quran in which a woman's lone witness will cancel that of a man. This is the case of mutual recrimination mentioned in 24:6-9. The matter here is that if a man accuses his wife of infidelity, he is to testify five times that he is speaking the truth. Then his wife, in her defense, can testify five times that her husband is a liar. Following this testimony, she goes free.
Why is the husband to testify five times? In the Quranic context, it is obvious that since he lacks witnesses, he is testifying once to make the claim, and four additional times, one in place of each non-existent witness. Even if we presume that the witnesses should have been all males, then consider the accused woman's counter testimony. She also testifies, once on her own behalf, and four additional times on behalf of the absent witnesses. It thus becomes clear that one woman's testimony is equivalent to one man's testimony. Moreover, the end result is that the woman's testimony cancels that of her husband in this case, given the principle of presumption of innocence. Hence it is incorrect to say that as a general rule a woman's testimony is worth less than that of a man.
Now we may ask why in the case of loan transactions the Quran put the matter as it did. The answer seems to be that there were factors at the time of the revelation that are unlike most of our present circumstances. First, women were mostly not savvy with business transactions. Second, when it comes to bearing witness and being cross-examined, in traditional societies men would have been expected to more likely hold to their testimony under pressure (usually coming from male interrogators, and sometimes from society more generally). Perhaps this is why the Quran said, "If you do not find two men, then a man and two women, so that if one of the women slips the other will remind her." (Quran 2:282)
The ideal situation was for two male witnesses to perform this community service, and if two men could not be found, then one man and two women. The Quran was thus sparing women at the time the stress of having to testify in court over and above all of her other traditional responsibilities.
The matter is of course very different today, as women can be seen to excel in a wide variety of fields, and there is no reason to suppose that their testimony is anything but equal to that of men. In conclusion, in our revaluation of the whole matter here, we have found that first, there is no reason for the classical scholars’ generalization from this specific case of loan transactions to cases in general. Second, the Quran’s treatment of this specific case may have a lot to do with the time and place of the initial Quranic impact.
But isn’t the Quran for all times and places? Yes, in terms of its delineation of Islam’s main beliefs and practices. However, while the Quran is indeed for all times and places, some specific legislation may have been conditional upon the circumstances in 7th Century Arabia. This seems to be one of those specific pieces of legislation.
We come away from this with the main Quranic teaching on the subject that the verse meant to convey. This is, incidentally, the longest verse of the entire Quran. Without going into all of its details, it suffices for our purposes here that the main point of the verse is to advise us to get our loan transactions properly written and witnessed so as to forestall future dispute.
But the next verse (Quran 2:283) shows the flexibility available to us in this matter. This latter verse shows that if we are on a journey and do not find witnesses then it is enough for the debtor to place some item in the possession of the creditor as a guarantee. However, if the creditor trusts the debtor, then the creditor’s confidence is sufficient as surety. According to the tafsirs of both Ibn Kathir and al-Qurtubi, many early commentators on the Quran held that this last proviso is what governs the whole discourse. That is to say that despite all the specifics given in the verse about writing the contract and getting it witnessed, if the two persons trust each other there is no need for a written contract or for witnesses.
Following from this view, I would add that since the writing and witnessing are not required, though these are stated in the grammatical imperative, neither is the stipulation about two women witnesses in the place of one male witness an imperative. That too is a recommendation to achieve the best outcome at the time and avoid disputes. But if the witnesses are trustworthy to the contracting parties, then neither the number of witnesses nor their gender is of crucial importance.
On this interpretation of the verse, what is significant is that we should repay our loans faithfully, and that if we are witnesses to such a transaction we should bear faithful witness for the sake of Allah. These are some of the lasting principles derived from the verses discussed above (Quran 2:282-83). To insist today on the number and gender of witnesses mentioned in the verse is a distraction from those main principles.
I hope that this clarifies the meaning of the verse and removes the misgiving that enters the modern Muslim mind that results from our common experience of men and women as equal players in the business world.