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pretendy

@pretendy-blog / pretendy-blog.tumblr.com

I'm a physics student at the University of Warwick, UK.
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Evolving clocks

The 21st century's version of creationism, intelligent design, can be summed up by the Blind Watchmaker argument - that like a watch, whose intricacy implies a watchmaker, life displays such vast complexity that it must be the result of a creator or designer. Intelligent design proponents will say that if you take the parts of a clock, put them in a box, and jumble it around randomly, you will never construct a working clock. Similarly, they say, random mutations in DNA cannot therefore be responsible for the evolution of complex life.

However, this is both a straw man and a false analogy. It's a straw man because it grossly misinterprets the theory of evolution. By drawing a false analogy between DNA replication and jumbling up cogs and springs inside a box, it presents evolution as some kind of 'Randomise' button on an Elder Scrolls character creation menu.

This is not the case.

So anyway this video is pretty cool. It deconstructs the straw man, and instead creates a true (or almost true) analogy between evolution and clock making. It presents a simulation of a large population of clocks, each with its own (initially random) genome, containing all the information about which components connect to which. At random, three clocks are selected and pitted against each other and measured for their ability to tell time. The loser is banished from the population and the winning two mate and create offspring. This process is repeated thousands of thousands of times, and guess what the result is? 

3 or 4 handed clocks which tick and tock with the utmost precision.

There are a couple of really interesting things I noted about this video:

  1. As the population evolves, the phenotype seems to stay in a stable 'phase' for a long period of time before undergoing (a first-order?) 'phase transition', where a new, more fit, phenotype quickly spreads across the population. 
  2. The transition period between two of these phases is very short, on the order of tens of generations. The author of the video points out that these transitional clocks are much less likely to be found in a fossil record.
  3. To evolve a three handed clock, there never has to be a 'two-and-a-half handed' clock. Again, an intelligent design proponent would talk about certain biological systems as being irreducibly complex. This simulation shows an example of when this need not be the case.

It's quite difficult to see whether or not 1 and 2 are fully an artefact of the program - simplifying the full complexity of life down to a few-component system - or whether or not they are an intrinsic (but more subtle) part of real evolution. I think it would be interesting to see if real populations underwent these kinds of phenotypic phase transitions over short periods of time (hundreds of generations).

Source: pretendy
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Life is blind.

How do we define life? If you asked this question to a biologist, he or she would point you towards the seven commandments of life science (‘thou shalt metabolise’; ‘thou shalt adapt’; ‘thou shalt reproduceetc.) Life, they would say, is a label we give to anything displaying these seven features. This stone tablet has been able to bestow the status of ‘living’ unto all the fish and trees and mushrooms and amoebae that biologists have so far wanted to study. However is this statutory definition enough? I don’t think it is. It seeks to sort any given collection of molecules into one of two camps: ‘living’ or ‘not living’. It’s a tautological distinction that takes no prisoners. Importantly, rather than attempting to form a truly encompassing definition, all it does is list seven characteristics that are common to everything that had already been colloquially defined as life! It is no more of a definition than an affirmation. It in no way reflects the complex nature of, well... Nature. An individual mammal and the cells inside it are both considered to be living in their own right. Contrast this with a swarm of bees which isn’t generally thought of as an organism in of itself, but rather a collection of organisms. Our intuition seems to only accept something as living if it’s encapsulated in its entirety by skin, scales or a membrane. Yet in many ways a swarm or hive will act as a single coherent organism when reacting to a stimulus. A hive is even organised into subsystems (workers, soldiers, a queen etc.) which all interact with each other in a way that’s fundamentally similar to the way cells interact in a mammal.

We live in hives too, but we call them cities. Cities are often described through metaphors such as ‘thriving’ or ‘alive’, but are these more than metaphors? A city metabolises coal to power and heat itself, it has a body clock and transport network, it’s organised into cells (us) which function to keep it homeostatic, it can grow and die, it adapts to environmental changes over time... Despite all this it we as humans remain very objectionable to the idea that a city might be an actual living organism. But then again, if a red blood cell could philosophise would it too reject the notion that its host was in some sense just as much an individual as it was? Would it not ascribe the seemingly intelligent behaviour of the human it lives in to the computational work performed by individual neurons that it supplies oxygen to rather than the human itself? The human would certainly ascribe intelligence to itself! Or its brain, where it considers the ‘seat of its consciousness’ to be. In what ways, then, is a computer different to a brain? While I’m not going to get into a discussion of consciousness, I will raise the question: do computers think? Well, they don’t think like a human, but that’s not to say they don’t in some sense think. In any case, the answer certainly isn’t either a yes or a no, but complex and multi-faceted one. And I think this is true not just of thought but of life itself. The questions raised here are ones that cannot be addressed (or even asked!) by the limiting definiton that biology has given us. In this sense it is blind to many possibilities of life that we could learn from. Life cannot be defined in such a way that makes it a binary digit (either living or not living). Nor should it be a scale of 1-10. If anything, it’s a many-dimensional vector. The seven pillars should not serve as committee in charge of (lifelong?) membership to the Living Club. Rather, they should be thought of as a set of features that emerge out of the complex behaviours characteristic to life and governed by evolution. Life, if anything is a single individual composed of sub-individuals, sub-systems, subsub-individuals, self-similar on many scales, all interacting, all ecompassing. It is a networked fractal array of cogs and axels but most of all: hugely, vastly, complex.

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