Why David Lewis was a unicorn who farted rainbows

Words solve coordination or discoordination problems.  That is why they are useful in solving collective action problems including that of disseminating information or imperatives (e.g. commands). 

Intension in philosophy refers to the internal meaning, sense, or defining properties of a word or concept, contrasted with its extension (the actual objects it points to in the world). 

The problem is that if an intension has epistemic content then it changes as our knowledge base changes. It has no well defined 'extension'. Pretending otherwise leads to a cascade of intensional ('masked man') fallacies. It is also the reason that you can meaningfully say 'I am not myself' or, indeed, 'no Consciousness coincides with itself'. Stuff like that sounds profound or mystical. It really isn't. 

Equally foolish are ipse dixit assertions that you have defined a philosophical position for yourself by arbitrarity restricting an intension to a particular, generally foolish or meaningless, extension. 

David Lews knew about Schelling focal points but his subsequent trajectory was as foolish as that of his colleagues. 

David Lewis, “Reduction of Mind”* 

I am a realist and a reductive materialist about mind.

If so, Lewis's entire knowledge-base contains nothing mentally constructed. But if this were the case for a member of our species, that person would not need a mind or a 'theory of mind'. In other words, such a person would not be a 'social animal'. He could have been raised by wolves. 

Was Lewis really such a person? No. Thus his statement about himelf is false. However, this does not mean he is a liar because he may have no intention to lie. He may simply be stupid. 

I hold that mental states are contingently identical to physical – in particular, neural – states.

Even if this were the case, if those neural states are supervenient on other neural states not directly linked to anything 'out there'- for example if they are self-evaluative- then there is no physical 'extension' for at least one of the 'intensions' involved. One might say 'but if there is a canonical (non arbitrary) extension of a physicalist type, then- even if we don't know what it is because our knowledge base is as yet incomplete- then one can be a 'realist' for the same reason that one can be a unicorn that farts rainbows because, one of these days, the Flying Spaghetti Monster will manifest and ensure that you will have always had the identity of a unicorn that farts rainbows.

...My reductionism about mind begins as part of an a priori reductionism about everything.

Which is like saying my being a flying unicorn begins as part of my a priori faith and confidence in the Flying Spaghetti Monster. 

This world, or any possible world, consists of things which instantiate fundamental properties

which are mental constructs of a provisional or ad hoc type. They aren't real our 'outside' the mind. On the other hand, the Flying Spaghetti Monster is definitely real.  

and which, in pairs or triples or . . . , instantiate fundamental relations.

Instantiation is like incarnation. The Flying Spaghetti Monster has already incarnated as Kamala Harris. When she becomes President, I will become- indeed, I will always have been, a unicorn which farts rainbows.  

Few properties are fundamental: the property of being a club or a tub or a pub,

are dependent on the mind or purely mental life of some person or bunch of people.  

for instance, is an unnatural gerrymander,

no. It is a more or less Schelling focal solution to a coordination or discoordination problem.  

a condition satisfied by miscellaneous things in miscellaneous ways. A fundamental, or “perfectly natural,” property is

not known to exist for anything actually known to exist. For all we know, everything evolves on an always uncertain fitness landscape.  

the extreme opposite. Its instances share exactly some aspect of their intrinsic nature. Likewise for relations.1 I hold, as an a priori principle, that every contingent truth

must conform to that a priori principle. If it doesn't, it isn't true. Thus the fact that there is no Flying Spaghetti Monster is a necessary truth. That I will become, or will have always been, a unicorn which farts rainbows may be considered a contingent truth. But, this may not be the case. Flying Spaghetti Monsters might, necessarily, for an a priori reason, have to create such unicorns.  

must be made true, somehow, by the pattern of coinstantiation of fundamental properties and relations.

e.g. those which turn people into unicorns which fart rainbows. 

The whole truth about the world, including the mental part of the world, supervenes on this pattern.

But supervenience relations are wholly mental and epistemic- i.e. they change (or are 'sublated') as our knowledge base changes. The truth is, only correlation may be observable. What is or isn't supervenience is, at best, a Bayesian guess. 

If two possible worlds were exactly isomorphic in their patterns of coinstantiation of fundamental properties and relations, they would thereby be exactly alike simpliciter.

Things which don't exist aren't exactly alike save in the sense that such resemblance can't exist.  

It is a task of physics to provide an inventory of all the fundamental properties and relations that occur in the world.

No. The task of physics is to use scarce resources in a regret minimizing way which is related to raising total factor productivity & species robustness to exogenous shocks.  

(That’s because it is also a task of physics to discover the fundamental laws of nature, and only the  fundamental properties and relations may appear in the fundamental laws.)

Only in the sense that it is the task of Physics to hasten the advent of the Flying Spaghetti Monster.  

We have no a priori guarantee of it, but we may reasonably think that present-day physics already goes a long way toward a complete and correct inventory.

Fuck off! The opposite is the case.  

Remember that the physical nature of ordinary matter under mild conditions is very well understood. 

No. All we can say is that Physics- i.e. manipulating things to get better outcomes- continues to pay for itself even though Metaphysics- i.e. claims to understand things- has turned into drooling imbecility.  

And we may reasonably hope that future physics can finish the job in the same distinctive style.

So, 'realism' is based on magical thinking. Physicists will soon discover how to incarnate or instantiate the Flying Spaghetti monster. I will always have been a unicorn which farts rainbows.  

We may think, for instance, that mass and charge are among the fundamental properties;

We know that this is a gross simplification. 

and that whatever fundamental properties remain as yet undiscovered are likewise instantiated by very small things that come in very large classes of exact duplicates.

Instantiation is not a concept in physics. Metaphysics isn't physics. It isn't even magic in that it does not promise you a larger dick if you sacrifice a cock to Hecate.  

We may further think that the very same fundamental properties and relations, governed by the very same laws, occur in the living and the dead parts of the world, and in the sentient and the insentient parts, and in the clever and the stupid parts.

What we may think does not matter if we study or teach low IQ subjects.  

In short: if we optimistically extrapolate the triumph of physics hitherto, we may provisionally accept that all fundamental properties and relations that actually occur are physical.

No. The opposite conclusion is better supported- viz. stuff we now think of as 'fundamental' is actually contingent or coevolved.  

This is the thesis of materialism.

Which may have seemed important when a lot of people were terrified that their immortal soul would burn for all eternity in Hell fire unless they gave money to some bunch of nutters. Such wasn't actually the case. Material incentives, or disincentives, to the clergy alter their behaviour. 

(It was so named when the best physics of the day was the physics of matter alone. Now our best physics acknowledges other bearers of fundamental properties: parts of pervasive fields, parts of causally active spacetime. But it would be pedantry to change the name on that account, and disown our intellectual ancestors.

Very true. Sadly Lewis doesn't describe himself as a Racist who believed the only good Injun is a dead Injun.  

Or worse, it would be a tacky marketing ploy, akin to British Rail’s decree

British Rail disappeared. Oddly, its successors were worse. 

that second class passengers shall now be called “standard class customers.”

Now they are called victims. 

If materialism is true, as I believe it is, then the a priori supervenience of everything upon the pattern of coinstantiation of fundamental properties and relations yields an a posteriori supervenience of everything upon the pattern of coinstantiation of fundamental physical properties and relations.

If, it is a synthetic a priori truth that the Flying Spaghetti Monster will turn me into a rainbow farting unicorn which has always existed then, a posteriori, I am such a unicorn.