|Lojban For Beginners — velcli befi la lojban. bei loi co'a cilre|
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The reason I have included this blindingly obvious piece of logic is that it demonstrates how sentences can be joined, and how 'because' can be turned into 'therefore'. We'll deal with the second part first, because there's a few issues about connecting sentences we want to leave till the next section. So for now, don't worry about .ije. Do worry, however, about ni'i.
What we have here is a proposition (Fluffy is a rabbit, and rabbits don't live long), and a conclusion (Fluffy doesn't live long.) So what is ni'i doing in front of the final selbri? Lojban treats sumti tcita the same as tenses; so ni'i can go in front of the selbri, as if it was a tense. This corresponds to an adverb like therefore in English; in terms of Lojban, however, it means the same as if you'd said ni'i zo'e 'because of something obvious' (in this case, the preceding two sentences). So in this construction, ni'i, used as a tense (or ni'i zo'e, using an ellipsed sumti) correspond to therefore.
But in the following sentence, where ni'i is a sumti tcita introducing a distinct sumti and not a 'tense', ni'i does not mean 'therefore'. As we'd expect, ni'i relates a sumti to its bridi through the gismu underlying ni'i, namely nibli 'logically necessitates.'. So ni'i means 'logically because':
la flufis. mrobi'o ni'i lenu ro ractu na'e ze'u jmive
Fluffy past die with-logical-necessity the-event all rabbits other-than long-time-period live
Fluffy died because rabbits don't live long.
But what is the sumti tcita for 'therefore'? How do we say the reverse — "Rabbits don't live long; therefore Fluffy died" — in a single sentence? As it turns out, we say it like this:
We have here a sumti tcita, seni'i, which means 'with the logical consequence that', i.e. 'therefore'. And this seni'i looks a lot like ni'i, the sumti tcita meaning 'logically because'.
ro ractu na'e ze'u jmive seni'i lenu la flufis. mrobi'o
Rabbits don't live long, with the logical consequence that Fluffy died.
Actually, you should have seen enough to work out the relation between the two from Lesson 9. As you saw there, sumti tcita can be modified with se, te, ve, xe, just like their underlying gismu. You know by now that the sumti introduced by ni'i is le nibli 'that which logically necessitates, the logical cause.' This means that se ni'i is a sumti tcita introducing le se nibli — 'that which is logically necessitated; the logical result.' So we have a pair: ni'i 'the logically necessitator, logically because', and seni'i 'the logically necessitated, logically therefore'.
We can apply this principle to the other sumti tcita we've looked at. Here are some examples:
le lante cu spoja ri'a lenu ri pu glare
the can explode with-physical-cause the-event it past is-hot
The can exploded because it was hot.
le lante pu glare seri'a lenu ri spoja
the can past is-hot with-physical-result the-event it explode
The can was hot, so it exploded.
so'i prenu cu nelci la djiotis. mu'i lenu ri xajmi
many people like Jyoti with-motivation the-event she is-funny
Many people like Jyoti because she's funny.
la djiotis. xajmi semu'i lenu so'i prenu cu nelci dy.
Jyoti is-funny with-motivated-result the-event many people like her
Jyoti is funny, so many people like her.
This is just like Exercise 1, except that now we have eight choices: ri'a, mu'i, ki'u, ni'i and their se forms. For each sentence, choose the most suitable sumti tcita.