Hey cool, that description explains some things.

From the 2nd paragraph of the "Extraverted Intuition" section:

an INTP will often make controversial, speculative points of argument, often annoying the discussion-partner, and make them in such a way as to leave the impression that he is very serious about what he says. In reality, the INTP is not actually even certain himself whether he really stands by what he is saying, but his Ne strongly suggests that there must be a core of truth there. The purpose then of his outspoken style of argument is to sharpen his own intuitive understanding by testing the reaction of the listener, and indeed to examine the logic of his own arguments in real time while speaking them out.
And from the 6th paragraph of the same section:

The chameleon behaviour can be particularly strong when discussing something. The INTP may even argue something that he doesn't really believe himself. Sometimes it is for the intellectual stimulation that comes with the challenge of arguing from a variety of standpoints. Otherwise, it may be to avoid early conflict before the situation has been fully assessed.
What a relief, so Phaedrus doesn't really mean it when he argues so strongly for some points. That's the case, isn't it, since Paul James's description perfectly describes Phaedrus, doesn't it?