WORLD LOGIC DAY

Yes, it's a thing, and it's today. Or to put it more formally:

(∃d ∙ d ∈ Dates ∧ d = World Logic Day) ∧ d = today

Making some assumptions about a predefined Dates set (or type, in programming-speak) and a formally defined element (or instance) called today.

A big shout-out, on a personal basis, to Professor Jim Davies of the University of Oxford, who taught me formal specifications using Z (meaning symbolic logic and set theory) when I started my MSc studies back in the day. (I eventually graduated with a distinction, which pleased me immensely.) It utterly transformed the way I thought about software design.

While most people don't use formal specifications to design systems unless any bug is likely to kill people (e.g. flight control software), every modern software engineer uses automated unit tests (e.g. JUnit for Java), and every test case is actually an exercise in Hoare logic: setting up a pre-condition, executing code, and checking that the result is equal to the expected post-condition.

The difference is that in formal specifications, the pre- and post-conditions would be generalised expressions rather than specific values.

Way to go! So different from writing code using pencils and pre-printed stationery, which I absolutely remember doing (although my first experience of coding, 50 years ago, was a remote dumb terminal with a screen and keyboard: as good as it got back then). The future is here, and it's great.

Logic underlies all rational thinking and civilisation itself, so what could be more deserving of celebration?

And to everyone, a benediction from someone truly associated with logical thinking.

Live long and prosper.