Bruce Braley wrote: > ..... I've heard that over half the mathematical > knowledge that exists was developed after WWII.
Of course, in some sense it's a meaningless statement (what does "half" mean in this context? One part of thinking mathematically is to be always alert to fuzzy uses of numeric concepts -- not that they are always bad, but one must be wary of arguments in which they are used). The usual justification for the statement is something like the number of pages of math published in research journals, or the number of theorems stated. It's a useful exercise to think of all the factors that could distort such measures, from the increasing redundancy of modern research to the smaller page size in modern journals.
Even more importantly, it isn't clear that the increase in mathematical knowledge of the last 50 years itself justifies ANY change in mathematics education. The new knowledge rests upon the same foundations as the old knowledge. A student with the best 19th century education (and perhaps a quick update on modern notation and the advantages of computers) would be starting from a better position to understand high-level modern math than a student with an average 1990s education.
Changes in mathematics education should be justified on specific changes in educational needs or specific pedagogical advantages to be gained through the use of technology, not on some vague idea that older skills are no longer needed because they are old.