We do not know that the territory is single- level. It is conceivable that it is not, and the available evidence does not exclude the possibility.

The territory is single level...... BY DEFINITION ....... waaaahahahahahahahahahaha !!!!!

Things in thingspace commonly coming within the boundary 'free will' :

moral responsibility could have done otherwise possible irrational action possible self-sacrificial action gallantry and style (thanks to Kurt Vonnegut for that one) non-caused agency I am a point in spacetime and my vector at t+1 has no determinant outside myself whimsy 'car c'est mon bon désir' absolute monarchy you can put a gun at my head and I'll still say 'no' idealistic non-dualism consciousness subtending matter disagreeing with Mum & Dad disagreeing with the big Mom & Pop up there in the White House armed response no taxation without representation ... no taxation even with representation (daft ) 'No dear not tonight I've got a headache....' ....

aw hell, just go read Dennett : 'Elbow Room', he did it better than I could.

You've forgotten one important caveat in the phrase "And the way to carve reality at its joints, is to draw your boundaries around concentrations of unusually high probability density in Thingspace." The important caveat is : 'boundaries around where concentrations of unusually high probability density lie, to the best of our knowledge and belief' . All the imperfections in categorisation in existing languages come from that limitation. Other problems in categorisation, like those of Antonio, in 'Merchant of Venise', or those of the founding fathers who wrote that it is 'self evident that all men were created equal' but at the same time were slave owners, do not come from language problems in categorisation, they would have acknowledged that Shylock or the slaves were human, but from different types of cognitive compromise. Apart from that, it's an intellectually satisfying approach, and you might, if you persevere, end up with a poor relation to an existing language. Why a poor relation ? because it would lack nuance, ambiguity, and redundance, which are the roots of poetry. It would also lack words for the surprising but significant improbable phenomenon. Like genius, or albino. Then again, once you get around to saying you will have words for significant low hills of probability, the whole argument blows away. Bon courage.

Firstly, saying "you can define a word any way you want" is not the same thing as "any way which is meaningful to you". Secondly, I don't believe the development on entropy has anything to do with the convenience of using short words for often used concepts. "chair" is a meaningful piece of jointed reality not because of its intrinsic physical properties but because of its handiness for humans. A dolphin would find "chair" as a significant piece of jointed reality absurd. Thirdly, there is an obvious distinction bewteen using language descriptively and using it predictively. I would agree with you that mistakes often arise when moving from the descriptive to the predictive incautiously. That doesn't, however, make the descriptive use of language invalid, or even unwise, 98% of the use of language is descriptive. (I have proof of that statistic, but it won't fit in this margin).

Psychoh, do not despair. Remember : "The real challenge can be played as a single-player game, without speaking aloud.". We are looking for the natural joints of reality, and that is a purely subjective assessment. Every single pair of phenomena in the Universe can be the subject of a natural join if the difference in one of their attributes happens to be a salient division for you. So draw the line around Christmas any way you want, just like you can draw the line around 'food things living in the sea' any way which is relevant to your way of fishing. Just don't speak it aloud.

While we're staking out the new language, I want a word for red flowers, because I like red flowers, and that is much more important to me than their genotype or taxonomy. Also, I want a special word for slightly-out-of-focus photos, which is a very important category for reasons I'm not at liberty to disclose. The joints of reality are articulated in a rather large number of dimensions. Carving it correspondingly is going to need one heck of a .... dictionary.

Ben, Rolf, no problem, I just thought that 'people who look at dictionnaries' was starting to be a category subject to sneaky connotations.. :)

I'll second Frank Hirsch's comment and add one point. I don't get this obsession with 'dictionary definitions' either. An etymological dictionary is endlessly fascinating precisely because it shows you the evolution of thought processes, concepts, and word usages, in action. Very much the opposite of the sort of table thumping that dictionaries are here supposed to give rise to. Eliezer's examples seem to be taken from a pretty toxic discussion environment

So if we have 100 pieces of information about phenomenon A, then we have 100 separate, weaker or stronger, potential categorisations, each with its own set of potential, weaker or stronger, inferences. All legit. and above board, nothing sneaky about it. One could imagine the interactions of these 100 sets of inferences as a multi-dimensional interference pattern, with some nodes glowing brightly as inferences re-inforce, others vanishing completely. The 101st piece of information will bring its own potential categorisation and an additional set of potential inferences. The alternative, I suppose, is just buying a whole truckload of hemlock and going round paying calls on all my friends......