Shabbat 144 - Milk purity
Earlier we discussed the juice that oozed out of a fruit , where the intention of the owner played a role. What if the owner had no specific intention for his fruit? In elucidating this, the Talmud discussed the laws of milk.
The basic rule of food is that it can becomes ritually impure only after it has been washed in a liquid . This liquid can be woman's milk; whether the milk came out with the woman's knowledge and satisfaction (she wanted to feed her baby) or if it was unintentional. By comparison, cow's milk makes food susceptible to impurity only if the owner milked the cow, but not if it dripped by itself.
This rule seems strange, and Rabbi Akiva objected: cow's milk has much wider use than the milk of a woman, and therefore it certainly should be able to prepare the food for impurity, even when it dripped by itself. And the Sages, who initially composed the rule, what do they answer? They say that a human is different and is more stringent in many respects, so you cannot derive laws from humans to animals. For example, human blood is also considered a beverage, based on the phrase " Blood of the slain he will drink. " A person is usually slain against his will, and still his blood can prepare food for impurity; therefore the milk of a woman, even coming out against her will, has the same property. This is not true for animals.
Art: Albert Neuhuys - A saucer of milk