No where in the quran we are told that witness of a woman is half of that of a man. The following is the only verses that we find in the quran. Does this verse give rise to such an idea?
Please discuss to see where does this idea come from.
002.282 * YUSUFALI: O ye who believe! When ye deal with each other, in transactions involving future obligations in a fixed period of time, reduce them to writing Let a scribe write down faithfully as between the parties: let not the scribe refuse to write: as Allah Has taught him, so let him write. Let him who incurs the liability dictate, but let him fear His Lord Allah, and not diminish aught of what he owes. If they party liable is mentally deficient, or weak, or unable Himself to dictate, Let his guardian dictate faithfully, and get two witnesses, out of your own men, and if there are not two men, then a man and two women, such as ye choose, for witnesses, so that if one of them errs, the other can remind her. The witnesses should not refuse when they are called on (For evidence). Disdain not to reduce to writing (your contract) for a future period, whether it be small or big: it is juster in the sight of Allah, More suitable as evidence, and more convenient to prevent doubts among yourselves but if it be a transaction which ye carry out on the spot among yourselves, there is no blame on you if ye reduce it not to writing. But take witness whenever ye make a commercial contract; and let neither scribe nor witness suffer harm. If ye do (such harm), it would be wickedness in you. So fear Allah; For it is Good that teaches you. And Allah is well acquainted with all things. If ye are on a journey, and cannot find a scribe, a pledge with possession (may serve the purpose). And if one of you deposits a thing on trust with another, let the trustee (faithfully) discharge his trust, and let him Fear his Lord conceal not evidence; for whoever conceals it, - his heart is tainted with sin. And Allah knoweth all that ye do.
The quranic verse under consideration has nothing to do testimony of a woman being half of a man.
As is obvious the verse is about civil contract between two parties. We are simply advised that if we have witnesses it is better but if we do not at all then deal is still valid and it is upto parties to trust each other or not. If parties are willing to trust each other that is their business otherwise it is better for them to draw a contract in presence of witnesses. In short witnesses are not necessary at all regardless men or women. If parties deem them necessary, they can have any combination of winteses eg up to one man and two women.
From this verse it is not right to draw conclusions for wintesses for criminal cases. Here parties can have wintesses who ever they like or none at all, whereas in criminal cases victims do not choose witnesses rather whoever is present at the time of crime is the witness regardless man or woman, one witness or one hundred witnesses. The idea is to simply prove allegation beyond any reasonable doubt. Whatever way is employed is fine that serves the purpose.
As aleady explained in my other posts, law and justice related aspects need to be balanced properly to keep society as safe as possible. It is wrong to get innocent charged or convicted and likewise it is wrong to let criminals walk free. Crime detection is as important as getting convictions.
The main point to realise is the fact that the quran does not state any complete set of laws as instructions for carrying out. What the quran states is manily as guideline and advisory as a frame work to work within. The proof is existence of books of fiqh ie they are full of laws about things which peoole needed but they were not found in the quran or the ahadith.
The quran does not say anywhere that testimony of a woman is half of a man. Because the quran is based on principle of social justice an fairplay we can say that the testimony of all adults carries same value regardless male or female.