he is speaking to people who are familiar with MB. in their lingo the model goes like this (for intp):

Ti Ne Si Fe

So dominant = Ti, Aux. = Ne, Tertiary = Si, and inferior = Fe. He is just trying to get the idea of the N vs. S or T vs. F conflict across not saying that those particular functions conflict but is using their model as the method of the translation of this idea. However like you pointed out his worrds were poorly chosen because it would probably make people think that Si and Ne or whatever fight one another.