Hyperintensional vagueness

“Water” and “H₂O” don’t mean the same thing in ordinary English: it is not a priori that water is H₂O. But I suspect that when a chemist uses the word “water” in the right kind of professional context, they use it synonymously with “H₂O”. Suppose this is right. But what if the chemist uses the word with fellow chemists in an “ordinary” way, telling a colleague that the tea water has boiled?

Here is a possibility: we then have a case of merely hyperintensional vagueness. In cases of merely hyperintensional vagueness, there is vagueness as to what an utterance means, but this vagueness has no effect on truth value.

I suspect that hyperintensional vagueness is a common phenomenon. Likely some people use “triangle” to mean a polygon with three angles (as the etymology indicates) and some use it to mean a polygon with three sides. (We can capture the difference by noting that to the latter group it is trivial that triangles have three sides while for the former it is a not entirely trivial theorem.) But consider a child who inherits the word “triangle” from two parents, one of whom uses it in the angle way and the other uses it in a side way. This is surely not an unusual phenomenon: much of the semantics of our language is inherited from users around us, and these users often have hyperintensional (or worse!) differences in meaning.

Pain and water

One way for physicalists to handle the apparent differences between mental and physical properties is to liken the difference to that between water and H₂O. It is a surprising a posteriori fact that water is H₂O. Similarly, it is a surprising a posteriori fact that pain is physical state ϕ₁₃₅ (say).

Now, a posteriori facts are facts that are knowable by observation. But it is not clear that the proposition that pain is physical state ϕ₁₃₅ is knowable by observation.

Here is why. There are two main candidates for what kind of a state ϕ₁₃₅ could be: a brain state or a functional state. The choice between these two candidates depends on how strongly one feels about multiple realizability of mental states. If one is willing to say that only beings with brains like ours—say, complex vertebrates—feel pain, one might identify ϕ₁₃₅ with a brain state. If one has a strong intuition that beings with other computational systems anatomically different from those of complex vertebrates—cephalopods, aliens, and robots—could have consciousness, one will opt for identifying ϕ₁₃₅ as a functional state.

But in fact, assuming pain is a physical state, there is a broad spectrum of physical state candidates for identifying pain with, depending on how far we abstract from the actual physical realizers of our pains while keeping fixed the broad outlines of functionality (signaling damage and leading to aversive behavior). If we abstract very little, only brain states found in humans—and perhaps not all humans—will be pain. If we abstract a bit more, but still insist on anatomical correspondence, then brain states found in other complex vertebrates will be pain. If we drop the insistence on anatomical correspondence but do not depart too far, we may include amongst the subjects of pain other DNA-based organisms such as cephalopods. Further abstraction will let in living organisms with other chemical bases, and yet further abstraction will let in robots. And even when talking of the fairly pure functionalism applicable to robots, we will have serious questions about how far to abstract concepts such as “damage” and “aversive behavior”.

The question of where in this spectrum of more and more general physical states we find the state that is identical with pain does not appear to be a question to be settled by observation. By internal observation, we only see our own pain. By external observation, however, we cannot tell where in the spectrum of more and more general (perhaps along multiple dimensions) physical states pain is present, without begging the question (e.g., by assuming from the outset that certain behaviors show
the presence of pain, which basically forces our hand to a functionalism centered on those behavior).

Objection 1: An experimenter could replace the brain structures responsible for pain in her own brain by structures that are further from human ones, and observe whether she can still feel pain. Where the feeling of pain stops, there we have abstracted too far.

Response: There are serious problems with this experimental approach. First, mere replacement of brain pain centers will not allow one to test hypotheses on which what constitutes pain depends on the larger neural context. And replacement of the brain as a whole is unlikely to result in the experimenter surviving. Second, and perhaps more seriously, if replacements of the brain pain centers commit the same data to memory storage as brain pain centers do, after the experiment the agent will think that there was pain, even if there wasn’t any pain there, and if they have the same functional influence on vocal production as brain centers do, the agent will report pain, again even if there wasn’t any pain there.

Objection 2: We could know which physical state pain is identified with if God told us, and being told by God is a form of a posteriori knowledge.

Response: It seems likely that God’s knowledge of which physical states are pains, or of the fact that water is H₂O, would be a priori knowledge. God doesn’t have to do scientific research to know necessary truths.

Objection 3: We can weaken the analogy and say that just as the identity between water and H₂O is not a priori, so too the identity between pain and ϕ₁₃₅ is not a priori, without saying that both are a posteriori.

Response: This is probably the move I’d go for if I were a physicalist. But by weakening this analogy, one weakens the position that it defends. For it is now admitted that there is a disanalogy between water-H₂O and pain-ϕ₁₃₅. There is something rather different about the mental case.

Animals

Suppose that somewhere in the galaxy there is a planet where there are large six-legged animals with an inner supportive structure, that evolved completely independently of any forms of life on earth and whose genetic structure is not based on DNA but another molecule. What I said seems perfectly possible. But it is impossible if animals are simply the members of the kingdom Animalia, since the six-legged animals on that planet are neither DNA-based nor genetically connected to the animalia on earth.

On the other hand, the supposition that somewhere (maybe in another universe) there is water that does not have H₂O in it is an impossible one. So is the supposition that there are horses without DNA.

So the kind animal is disanalogous to the kinds water and horse. The kind water is properly identified with a chemical kind, H₂O, and the kind horse is properly identified with a biological species, Equus ferus. But the kind animal does not seem to be properly identified with any biological kind.

One can have DNA-based animals and non-DNA-based animals. If the Venus fly-trap evolved the ability to move from place to place following its prey, it would be an animal, but still a member of Plantae. Animals are characterized largely functionally, albeit not purely functionally, but also in reference to the function of their embodiment—there cannot be any animals that are unembodied.

Is animal a genuine natural kind? Or is it a non-natural kind, constructed in the light of our species’ subjective interests? I don’t know. I take seriously, though, the possibility that there is an "Aristotelian" philosophical categorization that goes across biological categories.

Deep Thoughts XXXIV

H₂O is nothing but water.

Would it have been crazy to think everything is made of water?

According to Aristotle, Thales held that the whole physical world is made out of water.  I don't know if Aristotle was an accurate interpreter of Thales, but let's suppose he was.  The claim that the whole physical world is made out of water seems really wacky.

But I think it was quite defensible before we got the successes of modern chemistry.  And I want to sketch one line of thought why.  I am not claiming that this line of thought was in fact Thales'.  But it could have been: it won't rely on any science inaccessible to Thales.  The line of thought has three steps.

Step 1. All liquids are the same substance.

Here is a line of thought towards this.  Granted, obviously samples of liquids differ widely in shape, color, opacity, taste, wholesomeness, viscosity, miscibility, temperature and inebriativeness.  But such variability does not challenge the claim that all liquids are in fact forms of the same substance.  After all, apples differ widely in size, color, taste, wholesomeness and hardness, but they are all fundamentally apples.  Moreover, samples of liquids apparently of the same sort can differ in most if not all of the above properties.  The most obvious are shape and temperature: simply by varying the environment, the shape and temperature of a sample of a liquid can change.  More interestingly, the opacity, taste and inebriativeness of grape juice changes over time.  The viscosity and at least apparent miscibility of honey changes over time.  The taste and wholesomeness of milk change significantly very quickly.  It is a very reasonable hypothesis, then, that mere differences in these observable qualities do not correspond to a fundamental difference in kind, that the grape juice and the wine, or the milk and the yogurt, are one and the same liquid, despite significant differences in causal powers.  But the differences between water and, say, milk or oil seem to be precisely differences in respect of qualities that do not make for different kind of thing.

The alternate hypothesis of explanation of the differences in properties between liquids, and that is that they have different ingredients rather than different properties.  But there was good reason to doubt this alternate explanation.  The significant changes happening in juice, milk and honey apparently do not require the introduction of any additional ingredients, nor the removal of any ingredients.

Step 2. All liquids are water.

If all the liquids are forms of the same kind of substance, we may want to figure out what the basic, generic or fundamental form of that substance is.  And here water seems a very plausible choice.  It is colorless, transparent, tasteless, devoid of medicinal effects except relief of thirst (which it shares with many other common liquids), non-viscous, quite miscible and non-inebriative.  It is reasonable to suppose, for instance, that when water acquires the properties of whiteness, milky taste and a bit of viscosity, it becomes milk.  One might wonder: how does one get water to acquire these properties?  Well, a reasonable thing to say is that female goats make rainwater acquire milky properties.  Certainly, when you stop the access to water, the goats stop making milk (and die).

Water, on this hypothesis, is the fundamental liquid, having the minimal set of properties needed for being a liquid, and when it acquires different properties, we call it by different names.

Step 3. Everything physical is water.

Step 3a. Everything solid is water.

Water can turn into a solid without anything being added to or substracted from it.  One might think that "cold" is being added to it, but supposing cold as a substance may be questionable (though, less so to the Greeks than to us), and besides if cold had to be added to water in order to turn it into ice, it would follow that the formation of ice should reduce the amount of cold in the air.  But the freezing of water does not appear to warm the surrounding air.

Furthermore, metallurgy shows that certain kinds of rocks can be turned into liquid, and then solidified into metals.  Some varieties of mud, which appears to be a particularly viscous liquid, can be solidified into brick or ceramic.  Sand can be melted into a clear liquid, and then solidified into glass.  Since Step 2 hypothesized that all liquids are water, it becomes very plausible to generalize to the hypothesis that all solids are water, too, albeit with the property of solidity.

Step 3b. All gases are water.

When water is heated, it turns into steam, which looks like a cloudy form of air, and hence one can suppose that air is a kind of steam.  Smoke comes from solid objects when these are on fire.  Since solid objects are water by Step 3a, smoke is also water.  It is reasonable to hypothesize that all gases are water.

Step 3c. Fire is water.

This is perhaps the toughest step, intuitively.  Fire and water seem to be opposites.  But one might hypothesize that when water is added to fire, the fiery qualities of the fire simply become diluted by the water. Steam is hot and burns, though it does not glow.  Fire, thus, could be reasonably thought of as a particularly vivid kind of steam.

We can generalize from Steps 2-3c to conclude that everything physical is water.

Final remarks.  On this highly speculative interpretation, Thales' thesis stands in sharp contrast to ingredient-based theories of the natural world, such as we have in modern Mendeleevian and ancient four-element chemistries.  We do not need to posit differences in ingredients to explain differences between things.  We generally don't posit differences in ingredients to explain differences in shape.  So why should we posit them to explain differences in, say, color or taste?

Of course, if a particular ingredient-based theory comes to have significant predictive and explanatory power, Thales' thesis needs to be abandoned.  I do not think the four-elements theory that some other ancients preferred was all that superior in predictive or explanatory power.

Mendeleevian chemistry, on the other hand, was far superior in predictive and explanatory power over either Thalesian or four-elements chemistry.

Water

I've been making myself more of a nuisance than usual. I've been asking people whether ice and steam are water. Does it matter? Well, if ice or steam isn't water, then water is not just H₂O. And that is good to know. But the question sort of grew on me, as questions often do.

The result of my informal survey is that there is simply no consensus on the question. A number of people told me that ice that is frozen water, and hence it's water. On the other hand, my five-year-old son thought that ice is frozen water, and hence it's not water. At issue here, I suppose, is whether "frozen" is an alienans adjective like "fake" in "fake silk" (fake silk isn't silk). After all, as a colleague pointed out, a vaporized human isn't a human. The best argument I heard for the "ice isn't water" position was that if someone gives you a glass of just ice, and you say "I'd like some water in it", nobody will say "There already is water in it." But, still, there is no consensus.

So this is interesting. The case of water and ice is not a far-fetched case, like many cases in metaphysics. It's an entirely familiar, day-to-day case. And yet, as far as I can tell, our use underdetermines our meaning. Scary. If that's what happens with water, what about substance and simultaneity?

My linguistic intuitions are so polluted that they're barely worth asking about. But my inclination is to say that "water" is ambiguous in the way "man" is: there is water in the generic sense and water in the specific sense, and the water in the specific sense is the liquid phase of water in the generic sense. But the informal discussions make me unsure about this.