The Brisker Rav on teaching Hashkafa

The following is quoted in the name of the Brisker Rav (הרב מבריסק Volume 3 p. 179) with respect to the proper way to teach hashkafa.

... it is prohibited to teach students a number of opinions while explaining each opinion and how they differ, rather you should only teach the correct hashkafa

This statement of the Brisker Rav is clearly one of the points where MO and UO disagree. The Charedi world today follows this Brisker Rav to a T, they only teach the correct hashkafa. The MO world is more open to other hashkafic approaches and at least acknowledges that they exist and are valid.

However, the question we need to ask is, how do we know what is the correct hashkafa? There is no shulchan aruch in hashkafa and in fact the Rambam writes in a number of places that there is no psak in hashkafa (see Is there psak in hashkafa?).

I heard the following from R' CY Goldvicht Rosh Yeshiva of KBY. He was a talmid of both the Chazon Ish and the Brisker Rav and a big baal machshava. He once asked the Chazon Ish why he only talks in halacha to his talimdim, why doesn't he talk machshava? The Chazon Ish answered that in Halacha there are boundaries. We have the words of the tannaim, then amoraim, then rishonim, acharaonim and the shulchan aruch. If we go off the path we will see it right away. In machshava, when we interpret a midrash, we are trying to say pshat in the words of the tannaim with no intervening generations. (see To be mechadesh in machashava for more on this)

This applies to hashkafa as well, there is no shulchan aruch and therefore it is not so simple to know what is the correct hashkafa and what is not.