Begging the question - simpliciter or relatively ?
It is useful to draw a distinction within the concept of begging the question. Joashua Gert is helpful here :
... it is worth getting a little clearer about this notion. To begin with, it is possible to criticize an argument for begging the question simpliciter. This happens when the argument more or less directly assumes what is to be proven. Some attempts to justify a principle of induction in epistemology seem to beg the question in this way: they claim to provide an argument that the future course of the world will resemble its past course, but they base their argument on the fact that in the past, the past has always resembled the future, and they then use the disputed principle of induction to support that very principle. In contrast to question-begging simpliciter , there is also a relative form question-begging. That is, an argument can beg the question relative to one sort of opponent, but not relative to another. What this means is that the argument relies on a premise that the first opponent would reject, and offers no support for that premise, while the same cannot be said about the argument against the second opponent. To illustrate: both rule- and act-utilitarians beg the question against Kantians in this relative way, in holding that - at bottom - it is only utility that has normative significance. But neither sort of utilitarian begs the question on this matter, in this relative way, against the other. (Joshua Gert, 'Begging the Question: A Qualified Defense', The Journal of Ethics, Vol. 18, No. 3 (September 2014), pp. 279-297: 281.)
If a utilitarian, act- or rule, has a thought out, well-argued position (whether we think it watertight or not), it is not irrational for them in arguing against each other to beg the question against Kant. They can and should confront Kant elsewhere but in this precise context of argument, in which the point at issue is internal to utilitarianism, it strikes me as perfectly in order, in this limited way, to beg the question against Kant. One cannot take on all opponents at once.
Joshua Gert, 'Begging the Question: A Qualified Defense', The Journal of Ethics, Vol. 18, No. 3 (September 2014), pp. 279-297.
Richard Robinson, 'Begging the Question, 1971', Analysis, Vol. 31, No. 4 (Mar., 1971), pp. 113-117. (An amusing and not unsubtle argument to show that begging the question is not a fallacy at all. Ironic ? It hardly matters : just follow the argument.)
Allan Hazlett, 'Epistemic Conceptions of Begging the Question', Erkenntnis (1975-), Vol. 65, No. 3 (Nov., 2006), pp. 343-363.