In article <pk_Ws.104635$O02.20123@newsfe18.iad>, Nam Nguyen <namducnguyen@shaw.ca> wrote:
> On 26/02/2013 1:16 AM, Virgil wrote: > > In article <m%XWs.20125$mC2.392@newsfe29.iad>, > > Nam Nguyen <namducnguyen@shaw.ca> wrote: > > > >> On 25/02/2013 10:25 PM, Virgil wrote: > >>> In article <SDWWs.99982$Hq1.27823@newsfe23.iad>, > > > >>> Since I said "not always", any such situation shows I am right. > >> > >> I think you misunderstood my point: > >> > >> In the context of language structure truth verification, > >> your original statement would _always_ fail: because for > >> Ex[P(x)] to be true, P(x0) must be true for some _example_ x0. > > > > To know that something must be true for some x0, it need not be known > > for which x0 it is true, only that it is true for SOME x0. Which was my > > original point! > > Then, can you construct a _language structure_ that would illustrate > your point?
It is well known that there is an infinite decimal, x0, such that x0^2 = 2, but it is not known for which infinite decimal, x0, it is true. --