Principles
The ideas behind the system, and the decisions that shape all of it.
Paludal is a dozenal (base-12) system of units, built the way SI is built but counted in twelves. Time comes from a 24-hour day of 86,400 s (dec): the blink is 1/100,000 of a day (twelve to the fifth power, 25/72 s exactly), and every time unit up to the day is a power of twelve of it. Length comes from the speed of light, fixed at 2 × 10^7 (20,000,000, or 71,663,616 in decimal) paces per blink, which makes the pace about 1.45 m - close to the Roman pace. Mass comes from the Planck constant, chosen so that a cub of water (a cube 0;1 pace on each side) weighs a lib. Temperature, charge, amount and light are each fixed by a constant, as in SI, so every unit converts exactly to SI. Multiples and fractions step by twelve, which divides evenly by 2, 3, 4 and 6.
Decided: the system is called Paludal ("paludal units", "is that metric or paludal?"). Fallbacks if needed: Uncial (Latin uncia, a twelfth) or Passic (from passus, the pace - as metric is from the metre).
Why: named after its creator, as Fahrenheit, Celsius and Kelvin are - but hidden: Latin palus, paludis means "a marsh". It matches the Latin naming style of the units, and works as an adjective like "metric".
Advantage: a short name that works as an adjective ("paludal units") and fits the Latin unit names, without putting a person's name on show.
Decided: dozenal is the number system (base twelve) and Paludal is the system of units built on it, as decimal is the number system and metric the units.
Why: to keep the two separate. Base ten can be used without metric units, and base twelve without Paludal ones. Dozenal counting is long established (the Dozenal Society, SDN and the X / E digits all predate this), and Paludal doesn't claim to have invented it - only the units are new.
Advantage: either half can be taught, adopted or argued about on its own - dozenal counting doesn't stand or fall with these units.
Goals: as rigorous as SI (every unit defined by a fixed constant, exact conversion to SI), but human focused - everyday sizes and rules of thumb come first. A round constant is only a tie-breaker: any fixed value makes a definition exact (SI's c = 299,792,458 m/s isn't round), so where sizes are equally good for people, the one that makes a universal constant round is preferred.
Decided: the universal test: if people and another species had to agree units without access to the Earth, they could both arrive at Paludal's from physics, chemistry and maths alone. The only Earth-based inputs allowed are the day and the year (time of day and the calendar), which human life runs on.
Why: units that rest only on physics and maths could be shared with anyone - in principle even an alien species - and rebuilt anywhere, without an Earth measurement or object. Time is the exception because people live by the day and the year.
Advantage: every unit except time can be rebuilt from first principles, and anything that fails the test is easy to spot (see the table below).
Decided: adopt prior art. Where someone has already done something as well or better, use it rather than invent something new, and credit it (see Prior art).
Why: existing work has already been argued over and tested, and some people already use it. Paludal already adopts SDN, do / gro / mo, dek and el, and the dozenal clock.
Advantage: less to invent and less to learn, and Paludal fits in with the dozenal work already out there.
How each part of the system does on the universal test:
| Unit or value | Rests on | Universal test |
|---|---|---|
| blink, beat, breath, moment, chime | the SI second (caesium today, optical clocks later), sized to fit the day | allowed (time); ≈ 8 × 10^11 hydrogen 1S-2S periods for a universal explanation |
| pace | c (physics) and the blink | passes; its size follows from the day |
| lib, cub | h (physics), chosen so a cub of water ≈ 1 lib | passes: water is the same everywhere |
| riv, onus, imp | e (physics) | passes |
| grex | a count, chosen so molar mass ≈ atomic mass | passes |
| turn, prefixes, numbers | maths | passes |
| acidity | pure water | passes |
| tep (size) | k, chosen so freezing to boiling ≈ 100 | mostly: boiling depends on air pressure, which is the Earth's |
| tep (zero) | a defined number, 0 °t = 289;485 ta, chosen to match water freezing at the Earth's air pressure | the number can be rebuilt from k; the reason for it is the Earth's water (see Open items) |
| lam | the human eye's sensitivity, at 540 THz | fails (SI's candela has the same problem) |
| vox (zero) | the threshold of human hearing | fails (human biology) |
| navis | the Earth's meridian | fails (navigation on Earth only) |
| parax | the Earth's orbit (AU) | fails (like the parsec) |
| years, calendar | the Earth's orbit | allowed |
- The failures are all human conventions on top of the core: an everyday temperature zero, how bright light looks to us, how loud sound is to us, and Earth navigation. None of them is needed to define another unit, except that the lam is one of the seven base units