Well shucks

Brownfemipower/La Chola has deleted her site. When I last checked, this link went nowhere. Which is a real shame, and I hope she eventually starts writing again.

–IP

Hello world — a public service announcement

If you know who I am and I don’t know that I know you offline (if you see what I mean), it would be nice and polite if you were to let me know who you are. If you don’t feel like announcing your identity to the world, you can drop me an email (irrational_point at yahoo dot co do uk, or one of my other email addresses) and let me know that you are reading and what screenname you are using for commenting.

Ta.

–IP

(21/03/08, 4pm — Edited for clarity. Sort of.)

March Scientiae

The March edition of Scientiae (a carnival for/about women and minorities in science) is up at Skookumchick’s Rants of a Feminist Engineer, and it’s the blogiversary edition.  There are lots of really good posts, so head on over and check it out.

–IP

Moving day

Welcome to the new cyber-soapbox! Please do help yourselves to some tea and coffee and biscuits. Make yourselves at home. Don’t mind the dust, I’m still graffitiing decorating.

I’m leaving the old Soapboax, because it feels rather, well young. Some of the things I’ve posted I’m not sure I still agree with. Some of the things I know I don’t agree with anymore — some of the things I’m ashamed of. I’ve been harsh to people, I’ve been naive, I’ve though about things in a very black-and-white way, I’ve been uncompromising.

Time to grow up a little. I’ll still leave The Soapbox up as archives, but I’m moving to a new blog. Anyway, all the cool kids seem to be WordPressing. Why not?

Why “modus dopens”, I hear you cry? A good question.

As any logic student knows, there are some argument forms in propositional logic that one sees again and again.

1. Modus ponens:
   If P then Q, P. Therefore, Q.
   Formally: P → Q, P ∴ Q
2. Modus tollens
   If P then Q, not Q. Therefore not P.
   Formally: P → Q, ~Q ∴ ~P

Both modus ponens and modus tollens are valid argument forms in propositional logic.

The third argument form is modus dopens, which earns its name through being both invalid and commonly mistaken for valid.
If P then Q, not P. Therefore not Q.
Formally: P → Q, ~P ∴ ~Q

I distinctly remember a logic tutorial in my first year in which the tutor wrote modus ponens and modus tollens on the board, and everyone dutifully took notes. He then proceeded to nearly choke himself sniggering as he wrote modus dopens on the board too, and saw about three people get that it was invalid and thus spot the connection with its name, while ten other students looked up blankly and proceeded to dutifully write it down in their notes.

–IP