Logician scene from the Grail album

Good evening.  The last scene was interesting from the point of view of a 
professional logician because it contained a number of logical fallacies, 
that is, invalid propositional constructions and syllogistic forms, of 
the type so often committed by my wife.  "All wood burns," states Sir 
Bedivere, therefore he concludes all that burns is wood.  This is, of 
course, pure BOOLSHIT.  Universal affirmatives can only be partially 
converted, all of Elmer Cogan is dead, but only some of the class of dead 
people are Elmer Cogan.  Obvious, one would think.  However, my wife does 
not understand this necessary limitation of conversion of apropositions.  
Consequently, she does not understand me; for, how can a woman expect to 
appreciate a professor of logic if the simplest cloth-eared syllogism 
causes her to flounder.  For example, given the premise all fish 
live underwater, and all mackerel are fish, my wife will conclude not 
that all mackerel live underwater, but if she buys kippers it will not 
rain, or that trout live in trees, or even that I do not love her 
anymore.  This she calls using her intuition.  I call it crap, and it 
gets me very irritated, because it is not logical.  "There will be no 
supper tonight," she will sometimes cry, upon my return home.  "Why not," 
I will ask.  "Because I have been screwing the milkman all day," she will 
say, quite oblivious to the howling error she has made.  "But," I will 
wearily point out, "even given that the activities of screwing the milkman 
and getting supper are mutually exclusive now that the screwing is over, 
surely, then, supper may now logically be got.  "You don't love me 
anymore," she will now often postulate.  "If you did, you would give me 
one now and again, so that I would not have to rely on that rancid 
Pakistani for my orgasms."  "I will give you one, after you have got me 
my supper," I now usually scream, "but not before," as you understand, 
making her bang contingent on the arrival of my supper.  "God, you turn 
me on when you're angry, you ancient brute," she now mysteriously 
deduces, forcing her sweetly throbbing tongue down my throat.  "Fuck 
supper," I now invariably conclude, throwing logic somewhat joyously to 
the four winds.  And so, we thrash about on our milk-stained floor, 
transported by animal passion, until we sink back, exhausted, onto the 
cartons of yogurt.  I'm afraid I seemed to have strayed somewhat from my 
original brief, but in a nutshell, sex is more fun than logic.  One 
cannot prove this, but it is, in the same sense that Mount Everest is, or 
that Elmer Cogan isn't.  Good night.