Properties

We have seen, here and there, instances of Lojban expressions of properties. Lojban treats properties as abstractions, introduced by ka. There is nothing controversial about that; properties are things you can talk about (sumti), which involve relationships and characteristics (selbri.) So if xendo means 'kind', for instance, le ka xendo refers to 'kindness'.

The thing about properties, though, is that they are properties of something. They are associated, not just with a selbri, but with a particular place of the selbri. For example, kindness is not just le ka xendo, but the property of someone displaying kindness — as a characteristic of that someone. In other words, not just le ka xendo, but le ka ___ xendo, where ___ stands in for that 'someone'.

As a further example, consider influence and susceptibility. Both involve the relationship expressed in Lojban as xlura:

x₁ (agent) influences/lures/tempts x₂ into action/state x₃ by influence/threat/lure x₄

So the Lojban for influence is le ka xlura. And the Lojban for susceptibility is... le ka xlura? Strictly speaking, yes: both properties involve the same bridi, xlura.

But obviously, we can't have the same expression for both influence and susceptibility; we have to have a way of highlighting the place in the bridi we are interested in. Though the two properties involve the same bridi, they focus on different places of that bridi. Influence is the property associated with the x₁ of xlura, the influencer. Susceptibility is the property associated with the x₂ of xlura, the influencee. So how do we say that in Lojban?

Lojban's solution to this problem is fairly similar to Lojban's approach to questions, as it turns out. Remember in Lesson 13 that the search for extraterrestrial intelligence was, in terms of Lojban, a search for the value to fit in the slot

leka ___ terdi bartu pensi

By the same token, influence is a property of things that fit into the x₁ place of xlura; so you can think of influence as leka ___ xlura. If we know that mi fits into the slot, we have 'my influence'; if we know that la fred. fits into the slot, we have 'Fred's influence'. And susceptibility is a property of things that fit into the x₂ place of xlura; so you can think of susceptibility as le ka xlura ___ (or le ka ___ se xlura.)

Lojban has a word for that slot associated with properties. It isn't ma, because you're not asking someone what fills the slot; you're just pointing out that there's a slot there that can be filled. It isn't ke'a either, because ke'a refers back to something you've already expressed as a sumti (though you might think of a relative clause as a property belonging to that sumti.) Property slots get their own KOhA cmavo, ce'u. So:

• Influence is le ka ce'u xlura "the property that x influences": anyone or anything that has that property can stand in for ce'u.

• Susceptibility is le ka xlura ce'u "the property that [something] influences x", or le ka ce'u se xlura "the property that x is influenced": anyone or anything that has that property can stand in for ce'u.

• And extraterrestrial intelligence is le ka ce'u terdi bartu pensi "the property that x is an earth-exterior thinker." You can tell whether you've found your Little Green Men by substituting them for ce'u, and seeing if the bridi is true:

  le ka lo fange pe la vulkan. cu terdi bartu pensi

If you cast your mind back to Lesson 7, you'll remember that we split up the abstractions Lojban uses into two main types: events, using nu, and facts or propositions, using du'u. A property, as introduced by ka, is still what we called there a reification. That means it's just like du'u: it's something you hold in your mind about what happens in the world, rather than something that objectively happens in the world. The difference is, ka has an empty slot, occupied by ce'u; and you're interested in the ka-clause only inasmuch as you're interested in what fills the slot. On the other hand, du'u-clauses don't necessarily have any such slot — although they can.

Most usage of ka in Lojban fits this pattern of 'filling a slot' straightforwardly. This is particularly the case when a ka-asbtraction is required in the place structure definition of a gismu: a ka-clause is required, because by its definition the gismu involves that slot. So with sisku 'seek', you search for ka-clauses, to find what will fill the slot. With karbi 'compare', you compare things to see how well they fit the slot. Or alternatively, the gismu by definition fills that slot, by relating the property to the value satisfying it. For example,

• mi fange do leka ce'u se krasi le bartu be le tcadu: I am alien to you in the property of "x₁ is from out of town" (as applied to me.)

• mi barda leka le xadni be ce'u cu clani: I am big in the property of "x₁'s body is long" — i.e. "x₁ is tall" (as applied to me.)

• mi mansa do leka ce'u pensi: I satisfy you that the property "x₁ is intelligent" applies to me.

What happens when you find the value that fills the slot? Then — and here Lojban parts ways with English — you no longer have a slot; so you no longer have a property. You've gone back to du'u. If mi mansa do leka ce'u pensi, that's the same as saying do djuno ledu'u mi pensi. A property applying to a known entity is no longer a property at all in Lojban, but a fact — or (if you no longer have to reify it) an event.

Be careful here: what English (and in fact, most traditional usage) calls properties are often actually considered just states in Lojban — that is, something that happens in the world, but without anybody lifting a finger. Being a runner (also known as 'running') is hard work; so we're happy to think of it as an event: nu bajra. But being happy (also known as 'happiness') is something that just happens, without any work; so we're inclined to call it ka gleki. But that's misleading. English distinguishes between running and happiness grammatically, because run is a verb and happy is an adjective. But verbs and adjectives don't mean anything to Lojban (or to many other languages), so there's nothing to say you can't say nu gleki instead. Much of the time, in fact, that is precisely what you should be saying. As a rule of thumb: if you wouldn't say ka bajra in a sentence, don't say ka gleki either.

Sometimes you'll want to speak of properties of applying to two entities at once. For example, the cop wants to know who talked about the heist, and to whom:

le pulji cu djica lenu djuno ledu'u makau tavla makau le nu jemna zercpa.

In that case, he's looking for both x₁s and x₂s to fill in his ka-property:

le pulji cu sisku leka ce'u tavla ce'u lenu jemna zerle'a To put it more formally, he is seeking pairs {.abu, by.} such that the proposition .abu tavla by. is true.

The main use for multiple instances of ce'u is our old friend simxu: if we want to speak about reciprocality, we are very much interested in which two places are related through that reciprocality:

mi ce do simxu leka ce'u tavla ce'u lenu jemna zerle'a

There are some reciprocalities that can be distinguished nicely in this way: simxu leka draci fi ce'u ce'u is a situation where people take turns writing plays for each other, while simxu leka draci fo ce'u ce'u is a situation where people take turns performing plays for each other.

Vocabulary

ckire		x1 is grateful/thankful to/appreciative of x2 for x3 (event/property)
mamta		x1 is a mother of x2; x1 bears/mothers/acts maternally toward x2; [not necessarily biological]