In the previous post, we discussed the fundamental disagreement between the ב"ח and all of the other פוסקים as to whether there is a rabbinical prohibition of mixing milk and meat when one of the components is from a non-kosher species. Everyone agrees that poultry, venison, etc., are only forbidden to be mixed with milk by Rabbinic decree. The question is how to properly understand the mechanics of this decree. According to most פוסקים, when the Rabbis added to the prohibition of בשר בחלב, they enacted new Rabbinic legislation that forbade poultry, venison, ect. They were concerned that allowing people to eat poultry/venison and milk would lead people to transgress the Biblical prohibition of meat and milk. However, they did not see fit to enact special legislation with regard to meat and milk from non-kosher species. Since these foods are already prohibited by virtue of their sources, adding a Rabbinical prohibition of בשר בחלב would not serve any purpose.
By contrast, the ב"ח maintains that when the Rabbis forbade poultry/venison with milk, it was not through the enactment of special prohibitive legislation. Rather, they simply decreed that the condition imposed by the Torah - namely, that to qualify for the prohibition of meat and milk the substances have to be from particular species - would no longer be in effect. Automatically, the prohibition extended to all forms of meat and milk, whether kosher or not. They were not inspired to decree a special prohibition of בשר בחלב on non-kosher meat and milk. But by suspending the Biblical rule that limits בשר בחלב to certain species, they necessarily included non-kosher meat and milk as well.
This distinction can help us understand another point of dispute between the ב"ח and many other פוסקים (although, in this case, the ב"ח is joined in his view by the מהרש"ל and the גר"א). We know that the Torah prohibits cooking, eating and benefiting from mixtures of meat and milk. The question arises: What about mixtures that are prohibited Rabbinically? Are these forbidden to be cooked and benefited from, or are the Rabbinic prohibitions on consumption only? Put simply: Am I permitted to cook chicken in milk as long as I don't eat it, or is cooking it forbidden as well?
The שלחן ערוך, the רמב"ם and nearly all other פוסקים state that, when it comes to poultry, venison and the like, only consumption is prohibited. Cooking בשר עוף or בשר חיה in milk is permitted, and the resulting combination is מותר בהנאה.
The ב"ח and a few others disagree and maintain that just as the Rabbis forbade the consumption of chicken and milk, so too did they prohibit cooking and benefiting from such mixtures. They reason that if the Rabbis gave these substances the status of בשר בחלב , then the full range of relevant prohibitions should apply. Granted, the prohibition in these cases is only Rabbinic, but shouldn't its form be identical to that of the Biblical injunction?
It seems we can explain the theoretical dispute here along the same lines as the previous מחלוקת, and in so doing we find that the ב"ח is highly consistent in his view. According to him, when the Rabbis forbade chicken or venison and milk, they did so by expanding the categories of בשר and חלב to include ALL species. They did not institute a new prohibition with its own format or parameters; rather, they left the prohibition as it was, and simply widened its range of applicability. Once the definitions of בשר and חלב are extended in this way, the entire gamut of איסורים associated with בשר בחלב- the prohibitions of cooking, eating and benefit - will apply to mixtures of fowl and venison with milk just as they apply to mixtures of beef and milk. There is no real basis for any distinction between the two.
By contrast, most authorities understand the prohibitions on mixing בשר עוף and בשר חיה to be distinct גזירות, Rabbinically decreed safeguards. In order to prevent people from mistakenly eating meat and milk, the Rabbis forbade the consumption of poultry/venison and milk. According to this view, the Rabbis did NOT expand the categories of בשר and חלב while leaving the form of the prohibition intact. In fact, they did the opposite - they left the Biblical categories intact and introduced a completely new set of Rabbinic strictures in order to accomplish their objective. Since these rules were separately legislated by the Rabbis, they do not have to follow the format of the Biblical law, and can therefore be limited to consumption but not to cooking or deriving benefit. In other words, according to these פוסקים, a mixture of poultry or venison and milk is NOT Rabbinically defined as בשר בחלב; if it were, all three prohibitions would have to apply. Mixtures of poultry/venison and milk are Rabbinically forbidden in their own right, under their own distinct heading, and the Rabbis only saw fit to forbid eating them.
In summary, we see that a difference in the way we conceptualize the mechanics of the Rabbinical prohibition on mixing poultry/venison with milk - whether we understand it as a widening of preexisting categories under the preexisting framework, or as a set of new and independently formulated safeguards - leads to a difference in the way these Rabbinical laws are applied in practice.