Saturday, 3 September 2011

Tim Tyler: Does the Lamarckian aspect of memetics make natural selection redundant?


Hi! I'm Tim Tyler - and this is a video which responds to one of Steven Pinker's criticisms of memetics - the one where he asks whether culture's Lamarckian component makes explanations of culture that invoke natural selection redundant.

In my book on memetics - which is out now - I take a look at some of the critics and criticisms of memetics. Steven Pinker is one of these critics. Pinker expressed a number of objections to memetics in a 2009 Harvard lecture. Here we will look at his notion that Lamarckian principle of "felt need" makes redundant those explanations of cultural evolution which invoke natural selection. Here's Steven:

[Steven Pinker]

The principle of "felt need" works a bit better in the cultural realm than it does in the organic realm. Cats can't grow claws in response to their desire to hang on to birds, but a human wants to hang on to something, they can often get a pair of pliers.

Lamarck's idea was, essentially, that organisms respond creatively to help them meet their needs.

Many organisms do, in fact, adapt in their own lifetimes to help them meet their needs. Plant roots grow around rocks, trees find the hole in the canopy where the light gets in. However this adapting often features only limited creativity - there are usually constraints on how far it can go. However, in the case of large-brained organisms, some fairly creative solutions are often possible. So, if you are smart - and you feel the need for some innovation or other - then you can often respond creatively, and make something that satisfies that need. So, the principle of "felt need" actually works - after a fashion - if you have a sufficiently big brain.

Notice, though, that how well it works depends on how smart you are. Having a big brain helps, but it doesn't solve every problem - so there are still some limits.

Creativity doesn't eliminate the need for selection. Rather it partially internalises selective processes. An intelligent creature can perform trials inside their head - seeing what works and what doesn't work in a mental simulation of the external world. Such simulations reduce the need for expensive real world trials. However, this doesn't really eliminate any selective processes, it just moves some of them from the real world into a simulated mental world inside the organism's mind.

Also, mental simulations are usually imperfect - so so real world testing is also needed, to see if what works in the mental world actually works in real life.

So, in reality there is plenty of cultural competition. Culture is not solely intelligently designed. Companies compete to sell products, charites compete for dontations, authors compete for readers, musicians compete for listeners - and so on.

To deal with cultural competition and failure, rather obviously, you need a theory that handles both mutation and selection - and evolutionary theory is the main theoretical framework for doing that. So, we need forms of cultural evolution and cultural genetics.

Directed mutations are a bit of a novelty for evolutionary theory - but it already handles a wide range of different types of variation - bit flips, inversions, duplications, deletions - and a wide range of types of ploidy change and symbiogenesis. Intelligently designed variation is just another mutation module to add to a long existing list of such modules - and it fits right in, thus allowing modeling of both genetic engineering and memetic engineering without any particular problems.

It may not make Pinker terribly happy to imagine creationists doing a jig at the thought of intelligent design being installed in the heart of evolutionary theory as a mechanism of mutation. However, that is pretty much what modeling cultural evolution demands. There's no getting around the fact that some variation is produced by large-brained organisms thinking the variants up. So long as you remember to only invoke intelligent design after some intelligent designers have evolved it really does not cause any problems.

Inevitably, some of those fighting the creationists will choke and splutter at the introduction of intelligent design into evolutionary theory - but they will just have to get a grip. Intelligently designed variations are not a form of magic. Although we can't fully do so today, someday, we will be able to "unpack" the intelligent cultural variations that arise inside brains and give an explanation for them in terms of the interaction of large numbers of unintelligent components.


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