This stanza was written just minutes before it was announced that Mr B. Johnson, sacked twice in the past for being a liar, had just become Prime Minister of the UK. He had been elected to that position, not by the country, but by members of the Tory Party, some of whom had only just joined the membership, adamant they wanted a No Deal Brexit and confident that Mr Johnson would be able and willing to provide it.
It appeared that his assertions and approach conjured up some sort of comfort zone for many of them, despite the fact that, by any normal standard, this magician has shown himself serially untrustworthy, even perhaps a fraud.
Furthermore, we all surely know that lies, fantasy and bluster do not provide a comfort that lasts. At some point, you are obliged to wake up and return to reality.
The “segments twain” in the stanza’s third line refer to a book by Iain McGilchrist called “The Master and his Emissary.” It is about the human brain and its two hemispheres.
The “master” is the right brain hemisphere, the “emissary” the left.
McGilchrist describes how the two hemispheres are neither equal nor simply complementary. And they are actually at odds, in tension, their partnership in question. The emissary doesn’t believe the master is necessary. The emissary counts and measures and fears. That’s all we are, or need to be, it “thinks”.
The emissary’s attempts to take over from the master threaten to destroy all of us, both sides.