"Do not walk to the truth, but dance. On each and every step of that dance your foot comes down in exactly the right spot. Each piece of evidence shifts your beliefs by exactly the right amount, neither more nor less. What is exactly the right amount? To calculate this you must study probability theory. Even if you cannot do the math, knowing that the math exists tells you that the dance step is precise and has no room in it for your whims." -- from "Twelve Virtues of Rationality", by Eliezer Yudkowsky
One of the more useful mental tools I've found is the language Lojban ( http://www.lojban.org/tiki/Learning ), which makes explicit many of the implicit assumptions in languages. (There's also a sub-language based on Lojban, called Cniglic ( http://www.datapacrat.com/cniglic/ ), which can be added to most existing languages to offer some additional functionality.)
One of the things Lojban (and Cniglic) has are 'evidentials', words which can be used to tag other words and sentences to explain how the speaker knows them: "ja'o", meaning "I conclude", "za'a" meaning "I observe", "pe'i" meaning "It's my opinion", and more. However, there hasn't been any easy and explicit way to use this system to express Bayesian reasoning...
... until today.
Lojban not only allows for, but encourages, "experimental" words of certain sorts; and using that system, I have now created the word "bei'e" (pronounced BAY-heh), which allows a speaker to tag a word or sentence with how confident they are, in the Bayesian sense, of its truth. Taking an idea from the foundational text by E.T. Jaynes, "bei'e" is measured in decibels of logarithmic probability. This sounds complicated, but in many cases, is actually much easier to use than simple odds or probability; adding 10 decibels multiplies the odds by a factor of 10.
The current reftext for "bei'e" is at http://www.lojban.org/tiki/bei%27e , which basically amounts to adding Lojbannic digits to the front of the word:
ni'uci'ibei'e | -oo | 0% | 1:oo | complete disbelief, paradox |
ni'upabei'e | -1 | 44.3% | 4:5 | |
ni'ubei'e | <0 | <50% | <1:1 | less than even odds, less likely than so |
nobei'e | 0 | 50% | 1:1 | neither belief nor disbelief, agnosticism |
ma'ubei'e | >0 | >50% | >1:1 | greater than even odds, more likely than not |
pabei'e | 1 | 55.7% | 5:4 | preponderance of the evidence |
rebei'e | 2 | 61.3% | 3:2 | |
cibei'e | 3 | 66.6% | 2:1 | clear and convincing evidence |
vobei'e | 4 | 71.5% | 5:2 | |
mubei'e | 5 | 76.0% | 3:1 | beyond a reasonable doubt |
xabei'e | 6 | 80.0% | 4:1 | |
zebei'e | 7 | 83.3% | 5:1 | |
bibei'e | 8 | 86.3% | 6:1 | |
sobei'e | 9 | 88.8% | 8:1 | |
panobei'e | 10 | 90.9% | 10:1 | |
pacibei'e | 13 | 95.2% | 20:1 | |
xarebei'e | 62 | 99.99994% | 1,500,000:1 | 5 standard deviations |
ci'ibei'e | oo | 100% | oo:1 | complete belief, tautology |
xobei'e | ? | ?% | ?:? | question, asking listener their level of belief |
By having this explicit mental tool, even if I don't use it aloud, I'm finding it much easier to remember to gauge how confident I am in any given proposition. If anyone else finds use in this idea, so much the better; and if anyone can come up with an even better mental tool after seeing this one, that would be better still.
.uo .ua .uisai .oinairo'e
I claim there is no meaningful "summary" of Lojban that constrains itself to eleven "rules", each less than a typical paragraph in length. The reference grammar covers most of the language, taking arguably 18 or 19 chapters to do so. Most of those chapters cover distinct classes of words, to boot.
There is an ancient log that mentions 11 rules in it, but that is just that -- ancient history (circa 1988! A quarter of the LW population wasn't even alive then!). It doesn't even pretend to be a reasonable catalog of the language. Perhaps they've updated since then, but a swift Googling doesn't bring up anything more recent.
In summary, lojban is a hard language mixing the worst of incompressible memorization (e.g., gismu places, lujvo, fu'ivla), archaic logic/maths (e.g., mekso), and just straight-up bad design. I liked it precisely because it was challenging and fun to hack on. At the end of the day, a person wanting to learn a new language is better served by learning a common natlang.
Why do you consider it to be bad designed? What fault did it's creators make?