ralju brivla deep structure
- lo si'o lo ralju brivla cu banzu = The idea that main verbs are enough
The Brivla Deep Structure Hypothesis is the hypothesis that the set of main verbs (mostly gismu) constitute a complete vector space for the expression of all meaning. In other words: that the Lojban main verbs set is sufficient to express all possible predicates, without separate lujvo, without tanru, and (here's the controversial bit) without prepositions. It presumes that all of these can be expressed with sentences (inordinately complex and ugly sentences, true) involving just the set of main verbs and cmavo (other than prepositions.)
Support and criticism
- It is not known what the minimum set of main verbs is to be. It is nevertheless agreed that most verbs in this set are gismu.
- Some Lojbanists (e.g. Adam and Nick) thinked most if not all prepositions in Lojban can be paraphrased as bridi: see pe necessary for sumti plus (BAI-type modifier) Gotcha.
- seljvajvo suggest ways in which lujvo (and by extension tanru) can be expressed as explicit combinations of gismu (be lo, be lo nu, je)
- most fu'ivla can be mostly (messily and verbosely) described in terms of pure Lojban, or at the very worst, foisted onto cmene
The hypothesis is probably the inception of hardlinerism; it proposes that much of Lojban grammar and semantics can be reduced to a simpler core. It was first formulated explicitly (unsurprisingly) by Nick Nicholas, in his lujvo paperswhich formulated seljvajvo. However, it is implicit in the very existence of the cmavo ta'u, which certainly predates him.
"Deep Structure" is Nick's allusion to Generative Grammar, particularly in its earlier, explicitly transformational form. The implication is specifically that other facets of Lojban grammar can be explicitly derived from this "Deep Structure", which is semantically primary.
This reveals my bias towards Generative Semantics
- OK, you can start yelling now :-)
- The theory, which may or may not be trivially false, is not as important as the ideology:
- Maybe skeplicre in the sense used in Epictetus.
This is an interesting philosophical discussion, but it seems to me that it doesn't quite grapple with the issue. Let me try out a few points:
- People can grasp meanings that are not expressible in natural language.
- Every natural language can express meanings that are unavailable in other languages.
- Lojban's gismu are unquestionably capable of expressing everything that's pragmatically necessary.
.i iuro'e uonai Let me try to follow out my line of reasoning.
- The hypothesis that "gismu constitute a complete vector space for the expression of all meaning" has two components. First, the gismu must cover "meaning space", whatever that is.
- That's easy. broda covers meaning space all by itself.
- Second, it must be possible to combine gismu to indicate any meaning in meaning space.
- That's hard. In fact, I think that my examples above show that it is false.
- This begs the question: What is the meaning space? Is it the set of all ideas that some person could, in principle, grasp? Is it the set of ideas that some one person could in principle communicate to some given other person? Is it the set of ideas that can in principle be communicated by a spoken language? Does it rely on the set of ideas that everyone can understand, that somebody can understand, that some person could in principle understand though in fact nobody living could? Et cetera.
- I rather think that meaning space itself is ill-defined.
So I conclude that the Gismu Deep Structure hypothesis, "gismu constitute a complete vector space for the expression of all meaning," is by itself neither true nor false; it is ill-defined (in the mathematician's sense). One needs to decide what it means before one can figure out whether it's true. (zo'o Of course, you can say that about anything in philosophy!)
But I also think that the GDS hypothesis is false under reasonable assumptions about the meaning space. English speakers know when to say "a" and when to say "the" and what they both mean, but I defy anyone to write a complete explanation, of any length, in any language, of what exactly the two words mean. Russian speakers know when to use perfective aspect and when to use imperfective and what they both mean, but again, I defy anyone to make a complete explanation. A language community may come up with a word for any concept they can agree on; I don't see a guarantee that that concept must be even comprehensible to outsiders, much less exactly expressible in an outside language.
A more general question is whether Lojban has the same level of expressiveness as a natural language. To me it seems to. It loses expressiveness by having a small vocabulary (translate "we dawdled on the scree"), but it gains by precision and flexibility.