There's somthing about Trevor

[marephraim]

No: HPFGUIDX 46529

jazmyn wrote:
> 
> Hard to say what other pets students had.  Note only the FIRST YEAR
> letter said 'Students may also bring an owl OR a cat OR a toad'.  

MarEphraim comments:

Of course, the question of the "owl or a cat or a toad" in re  Ron's 
rat and Neville's toad has arisen often (even I have been around 
long enough to notice the number of times it gets brought up).

Comment: In Symbolic Logic and the English Philosophy of the last 
century (you remember, Betrand Russell et al.) there is a fine 
logical/grammatical distinction between a conjunction and a 
disjunction.

In a conjunction (It is sunny [p] and the birds are singing [q]) 
both parts ('p' and 'q') must be  true for the conjunction ('p and 
q') to be true. This is considered a 'strong' truth requirement.

In a disjunction (It is sunny [p] or it is cloudy [q]) only one of 
the parts of the disjunction ('p', 'q') need be true for the whole 
disjunction to be true. You can think up examples where both parts 
_can_ be true, but onle one _must_ be true.) 

Now the interesting thing (to those of us offbeat enough to follow 
such things) is that a disjunction can accept any number of 
additional alternatives through a rule called addition ('p or q' may 
be expanded to be 'p or q or r or s... etc.'). 

This can be accomplished at will, whereas to add an alternative 'r' 
to a conjunction 'p and q' requires a much more stringent 
verification of truth. This is because all parts of a conjunction 
must be true for validity, while the truth value of any one or more 
parts of a disjunction automatically assigns an overall truth value 
to the disjunction.

Those of you patient enough (or bemused enough) to have read this 
far will see where I'm going with this one: The "Students may also 
bring an owl OR a cat OR a toad" statement need not necessarily be 
viewed as limiting the pets that students bring to only the listed 
species (doesn't Lee Jordan have a tarantula?).

MarEphraim (really needing to slow down on the coffee these days!)