Here is most of a post I first published on 28 12 2014. It raises the question of a rhetorical game which is as alive and kicking today as ever it was. I wrote about ....
... devices used by people whose intention is to dominate some particular discussion. I am inspired to do this more immediately by seeing a document headed CATHOLIC BISHOPS' CONFERENCE OF ENGLAND AND WALES Reflection Document for the Clergy on Marriage and the Family. It begins with a couple of pages of introduction in which some highly personal views are expressed, but without any indication of who wrote it, or of its status. (The drift of its argument makes it unlikely that it represents the united view of each and every individual bishop, unless they are truly a miraculously homogeneous group. There are, incidentally, signs of very hasty composition.)
More broadly, these months before the next  Synod are months in which people on each 'side' will be deploying their best rhetoric to promote their own strongly held prejudices. It seemed to me useful to point out some of the devices which can and will be used. I often use just such dodges myself; there is nothing shameful in doing so; I am criticising neither the anonymous episcopal ghost-writer nor anybody else. Equally, there is nothing shameful in analysing these smart tricks, as an aid to assessing the probative quality of a piece of argumentative rhetoric, and thus advancing dialogue.
I begin with BUT. BUT links up two statements and, I think almost invariably, privileges the statement which follows the BUT over the statement which precedes it. Often the statement before the BUT is put in solely to pre-empt and thus debilitate what could have been a powerful response*.
"You have worked for this firm for 45 years and you have always put its interests before your own or those of your family or even the dictates of Morality, but you are sacked".
There is an extremely fine example of this phenomenon in the CBCEW document.
"The Synod does not shirk from the truth of the Gospel and the Kingdom, urging us to make the demands of the Kingdom of God but this must be accompanied with a compassion and love, seeing firstly persons who are loved by God ..."
Here, the part which follows the BUT is clearly the part which the writer desires to promote as the dominating idea. This can be seen by inverting the sentence thus:
"[Action] must be accompanied with a compassion and love, seeing firstly people who are loved by God, but the Synod does not shirk from the truth of the Gospel and the Kingdom, urging us to make the demands of the Kingdom".
Whereas the first version can roughly be summarised as "Be nice", the second would as clearly suggest "Be strict". Yet each alternative deploys the same two data.
Another clever trick which BUT can play is to suggest polarised contradictions between key words or phrases in each half of a sentence. Thus, in this anonymous passage, "truth of the Gospel and the Kingdom/demands of the Kingdom of God" are clearly set in contrast with "compassion and love". The writer, an able rhetorician, skilfully contrives to smuggle into our minds the assumption that these are two ideas which pull in different directions. He or she hopes that you will not spot the logical possibility that "making the demands of the Kingdom" and "compassion and love" could be but two ways of saying the same thing. (One does not say "A must accompany B" if one believes that A and B are, in fact, identical.)