Bava Kama page 65, Bava Metzia page 14. Rambam laws of Theft chapter 1 law 14.

I would like to answer at least one question I asked on my previous blog entry on the Rambam. I think the Rambam is basing his opinion on the Gemara in Bava Metzia page 14 and also later in Bava Metzia page 101 where we have the law that a thief that improves the property that he stole can only keep the cost of the improvements, but the besides that the improvements go to the owner after the object is retuned to him. The situation is this in Bava Kama page 65. We know a thief has to pay double. Rav said the way this is evaluated is this. The main payment goes by the value of the object at the time of the theft. But to calculate the amount of the double, we go by the value of the object at the time of judgment. Rav Sheshet asked on this from a braita that says that if the object started out at one and ended up being worth four the double is calculated according to the time of the theft. The braita says the reason is that the thief can ask, "If I made the improvements, why should you get the profits?" The Gemara answers that Rav was talking about variations in market value, not improvements made by the thief. However, the Rambam says otherwise. He says if the object went from 2 to 4, and the theif broke the object, he pays according to the time of judgement. So, we see the Rambam means this to refer to any improvements. The Rambam I think based himself on the Gemara in Bava Metzia that all improvements to a stolen field or stolen object go to the owner. Only the theif can be repaid for the costs of the improvements. ---------------------------------------------------