Monday, November 17, 2008

Knee Deep in Reality

There are a number of hotly contested ongoing - and often thoroughly perplexing - debates in contemporary philosophy that hinge on there being a distinction between an internal and external world.

One example is the debate between externalist and internalist conceptions of mental content. In this debate, the externalist school suggests that the content of a belief about water - which we know is H2O - can only be true if it actually is about H2O. If the belief was referring to another substance that looked and tasted like water but was actually XYZ rather than H2O, then it's not strictly a belief about water.

An internalist denies this distinction, and is happy to accept a belief is about water based only on intrinsic properties to the individual possessing the belief. Whether it's about H2O or XYZ in the external world is irrelevant to attributing the belief to the person.

Another example is the even older debate surrounding realism versus anti-realism. Realism is the fairly intuitive thesis - uncritically accepted by the vast majority of us, including science as a whole - that things exist, and that they do so independently of us. Thus the world doesn't blink out of existence every time we blink.

Intuitive enough, but it's a bag of monkeys when it comes to determining what exactly realism means, to what it applies (objects, concepts, numbers, morals etc) and what its implications are. So trees might exist, but what makes a tree a tree? Is there some special quality possessed by all trees that non-trees don't possess? So is there some Platonic form of tree that itself exists independently of all individual trees that we know? If our sun goes nova and destroys the Earth, and along with it all the trees in existence, what does this mean for the existence of the concept of tree? Etc etc ad nauseum...

However, I suspect there's a ruddy great weakness to all these arguments, and to the debates in general.

I've tended not to get involved in the hurdy gurdy world of the metaphysics of realism or externalism, mainly because I've implicitly never really accepted the fundamental distinction between internal and external. I didn't really reflect on this much until recently, when discussing the implications of evolutionary ethics on metaethics - and I was bombarded with challenges concerning externalism versus error theory etc. I found myself unable to navigate this issue easily and ended up uncharacteristically speechless. A little homework later and I realise it's just because I think these debates start from a fallacy, and are so doomed to tie themselves in a knot.

Perhaps it's time to cut this Gordian knot...

Inside Out

What if the distinction between an internal and external world was fallacious? What if there were not two worlds to be reconciled, but only one? What if there's no intangible barrier between our bodies and minds and the world around us, but our bodies and minds are a part of the world?

The Stanford Encyclopaedia of Philosophy has a short definition of the internal/external distinction:
"Many contributors to the debate over externalism take internal properties to be physical properties of a creature that do not depend for their instantiation on any property instantiated outside the boundary of the creature’s body and brain." [my emphasis]
But I would suggest this distinction is far from self-evident. There appears to me to be an arbitrary boundary drawn between the body and the 'outside world'. But it seems to me that our bodies are part of the world. As are our brains. An as I'm an unapologetic physicalist about the mind, thus our minds are also a part of the world.

Vagueness is a crucial concept here. If you accept that it's impossible to draw any hard boundaries between physical objects, then you accept that the abstract definitions we give to those objects - be they 'hand', 'apple', 'water' - are also at some level vague when applied to the world. So there are no nice, absolute, unambiguous types that be cleanly applied to physical objects. Putnam himself acknowledged this point in The Meaning of Meaning (1973), before introducing Twin Earth.
there are things of which the description ‘tree’ is clearly true and things of which the description ‘tree’ is clearly false, to be sure, but there are a host of borderline cases. Worse, the line between the clear cases and the borderline cases is itself fuzzy.
So the fallacious distinction between internal/external appears to be based on our intuitions about there being non-vague distinctions in the world. There are also a bunch of intuitions about what constitutes self, as well as other illusions that contribute to our sense of consciousness. Dennett has spoken at length about the Cartesian theatre, and the intuitive impression we have of being somehow distinct from the world; that we're onlookers rather than participants. And it's possible to erode the sensation that we are distinct from the world.

So I'd contest that we're a part of the world; that we're not separate from it, but instead we're knee deep in reality.

It might not sound like much of a thesis, but I really think it fundamentally changes the way you look at debates such as those discussed earlier.

Now, that's not to say that distinctions and abstractions about 'trees' are not important. Or that notions of 'self', 'cause', 'meaning' or 'belief' aren't important. But they have to be seen in their proper context. We can abstract away and talk about 'trees' as if they existed as an independent entity rather than being just a vague set - and it might be useful to do so occasionally - but we can only take the metaphor so far before it breaks down. And we can only take the abstract notions of cause or mind or beliefs or a distinction between internal and external worlds so far before they break down.

So in some sense this perspective is anti-externalist. It's a kind of error theory: there really aren't any such things as 'trees' according to a hard and fast definition, and that has an impact on what someone means by 'tree'. But meaning is necessarily vague. Trying to pin meaning down is like trying to capture the reflection of the moon in a barrel full of water.

Just ask the practitioners of artificial intelligence. They've been trying to get machines to understand meaning for decades, and the best they can do is get a machine to seek out striped blocks because they taste 'good'. No-one would suggest the robots have any sense of what 'good' means, but they behave in a way that could give us the impression they do. Perhaps we're not so different.


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