in fact, he is not switchign from 1 to 2, but everywhere using 2. because argumentation is something different from two tape machines with different ‘arguments’(sic) loaded in set up to sound off with each other in a room. there are norms to argumentation. its called the apriori of argumentation
Frank van Dun,
The key to understanding the argument from argumentation is, first,
that when they are told or asked (not) to believe, say, or do something people
are likely and in fact entitled to question why they ought (not) to believe, say,
or do it; and second, that an exchange of arguments is a justificatory
argumentation only if all the participants acknowledge certain facts and abide
by certain norms—norms that no one can argue are invalid because
adherence to those norms is a necessary condition of engaging in
argumentation. In short, argumentation does not and cannot take place in a
normative void:
any truth claim […] is and must be raised and decided upon in the
course of an argumentation. And since it cannot be disputed that
this is so, […] this has been aptly called “the a priori of
communication and argumentation.” Now, arguing never consists of
free-floating propositions9 claiming to be true. Rather,
argumentation is always an activity, too. [… It] follows that
intersubjectively meaningful norms must exist—precisely those
which make some action an argumentation—which have special
cognitive status in that they are the practical preconditions of
objectivity and truth. Hence […] norms must indeed be assumed to
be justifiable as valid. It is simply impossible to argue otherwise,
because the ability to argue so would in fact presuppose the validity
of those norms which underlie any argumentation whatsoever.10