Category Archives: Mathematics

Business, Economics, Education, Mathematics, Media Criticism, Political Commentary, Science And Society, Technology and Society

Model Land

10 Comments

Judith Curry, on a new paper concerning how to escape from it:

Naïvely, we might hope that by making incremental improvements to the “realism” of a model (more accurate representations, greater details of processes, finer spatial or temporal resolution, etc.) we would also see incremental improvement in the outputs. Regarding the realism of short-term trajectories, this may well be true. It is not expected to be true in terms of probability forecasts. The nonlinear compound effects of any given small tweak to the model structure are so great that calibration becomes a very computationally-intensive task and the marginal performance benefits of additional subroutines or processes may be zero or even negative. In plainer terms, adding detail to the model can make it less accurate, less useful. [Emphasis added]

Computer models can be useful in some circumstances, but they are not science.

Business, Economics, History, Mathematics, Media Criticism, Political Commentary, Science And Society, Technology and Society

All the Doomsdays

15 Comments

Zero out of the last thirty predicted have actually come to pass. Someone should show this to Greta Doom.

Administrative, Business, Mathematics, Technology and Society

Email Problems

18 Comments

I’ve got a problem, that my system administrator won’t help me with. My Trash folder on the server has grown to several gigabytes, and there is no way for me to empty it. It slows down getting and deleting mail, but Thunderbird crashes when I even try to load it. Here is the helpful email I got when I asked to simply delete it on the server (which I can’t do, because I don’t have root privileges–on my own hosted server).

“You’ll need to access your email accounts with a proper email client from your PC to clear them out. We can’t just delete the mail from the server, then the indexes are messed up. You need to be properly emptying your trash. 

You have multiple Gigs of mail in the trash folders on the Simberg account. “

Note that this is nothing I don’t know, except I don’t understand why it would mess up indexes to delete the trash. Is that true?

[Update a while later]

OK, Tbird crashes, but I seem to be able to access it from Evolution. But there is no obvious way to empty it, other than to Expunge, which seems a little drastic, but maybe that’s what I have to do. And it doesn’t load all of the headers; it gets stuck at 99%.

[Update a while later]

Well, I hit “Empty Trash” in Evolution, and it seems to have done the job (even though Evolution says it’s still working on it).

OK, Evolution thinks it’s finished now. My next problem is that it’s not properly displaying my inbox. But now my web interface is much more manageable.