Depending on the cataclism of course, if all we have after it happens is knowledge, it will take years and years to get back into shape, just think about having to rebuilt the whole microprocessor industry, to the level it is today. YEARS...
Knowledge is good and all, but in the end we still need to convert that knowledge into somethign real, and getting it up from "nothing" requires a hell of a lot of time.
If then you think that the cataclism would be so bad that we are only left with knowledge, that means that infrastructures to make our lives as easy as they are today will not be there, therefore slowing down progress even more.
We would have to focus first and foremost on making our lives liveable, with infrastructures that are decent enough to be on par to today's ones, THEN we might have to think about advancing our technology to the point it is today.
If you just think about the time and effort it took us over the centuries to make sewer systems, electrics connections, bloody Broadband connections available to a *vast* percentage of the population, then you might be less optimistic about it all.
Without those and other every-day-life things, civilisation as we know it today is not possible, simply because *I BELIEVE* we are at today's level of technology mainly because we made it possible to have "easy lives" compared to 50 years ago. And because *there's many of us on this bloody planet*.
Take that away and we're back to the 17th Century. Lots of "knowledge" but no means (and no will in certain cases) to do something about it. Leonardo though about a "flying machine" centuries ago. He had the "knowledge". Look how long it took to make it possible to fly safely. Same for surgery, and let's not begin to talk about all those jobs and researches that need hugely precise technology.
But i don't think we're in for such a surprise to let
us somehow live, and destroy everything else. If something like that happens, then i don't think we would survive at all, or such a small number of people would survive, that even "knowledge" would not be there at all to advance our technology to the point it is today.