Chapter 10: Imaginary Journeys: The Lojban Space/Time Tense System
Humph, says the reader: this talk of “imaginary journeys” is all very well, but what's the point of it? — “zu'a” means “on the left” and “vi” means “nearby”, and there's no more to be said. The imaginary-journey model becomes more useful when so-called compound tenses are involved. A compound tense is exactly like a simple tense, but has several FAhAs run together:
✥3.1 le nanmu ga'u zu'a batci le gerku The man [up] [left] bites the dog.
The proper interpretation of ✥3.1 is that the imaginary journey has two stages: first move from the speaker's location upward, and then to the left. A translation might read:
- Left of a place above me, the man bites the dog.
In the English translation, the keywords “left” and “above” occur in reverse order to the Lojban order. This effect is typical of what happens when we “unfold” Lojban compound tenses into their English equivalents, and shows why it is not very useful to try to memorize a list of Lojban tense constructs and their colloquial English equivalents.
The opposite order also makes sense:
✥3.2 le nanmu zu'a ga'u batci le gerku The man [left] [up] bites the dog. Above a place to the left of me, the man bites the dog.
In ordinary space, the result of going up and then to the left is the same as that of going left and then up, but such a simple relationship does not apply in all environments or to all directions: going south, then east, then north may return one to the starting point, if that point is the North Pole.
Each direction can have a distance following:
✥3.3 le nanmu zu'avi ga'uvu batci le gerku The man [left] [short distance] [up] [long distance] bites the dog. Far above a place slightly to the left of me, the man bites the dog.
A distance can also come at the beginning of the tense construct, without any specified direction. (✥2.1, with VA alone, is really a special case of this rule when no directions at all follow.)
✥3.4 le nanmu vi zu'a batci le gerku The man [short distance] [left] bites the dog. Left of a place near me, the man bites the dog.
Any number of directions may be used in a compound tense, with or without specified distances for each:
✥3.5 le nanmu ca'uvi ni'ava ri'uvu ne'i batci le gerku The man [front] [short] [down] [medium] [right] [long] [within] bites the dog. Within a place a long distance to the right of a place which is a medium distance downward from a place a short distance in front of me, the man bites the dog.
Whew! It's a good thing tense constructs are optional: having to say all that could certainly be painful. Note, however, how much shorter the Lojban version of ✥3.5 is than the English version.