34. Rodney Brooks, �The relationship between matter and life,� Nature 409 (2001): 409-411.

34. Rodney Brooks, “The relationship between matter and life,” Nature 409 (2001): 409-411.

Rodney Brooks of the Artificial Intelligence Laboratory at MIT has long been a pathbreaking investigator in the construction of “AI” (artificial intelligence) and “Alife” (artificial life) systems. In this skeptical article, however, Brooks steps back from the bench to look critically at what AI and Alife research has actually demonstrated. He writes: 

...both fields have been labelled as failures for not having lived up to grandiose promises. At the heart of this disappointment lies the fact that neither AI nor Alife has produced artefacts that could be confused with a living organism for more than an instant. AI just does not seem as present or aware as even a simple animal and Alife cannot match the complexities of the simplest forms of life. (p. 409) 

The failures of these fields, Brooks argues, requires a diagnosis: 

We build models to understand the biological systems better, but the models never work as well as biology. We have become very good at modelling fluids, materials, planetary dynamics, nuclear explosions and all manner of physical systems. Put some parameters into a program, let it crank, and out come accurate predictions of the physical character of the modelled system. But we are not good at modelling living systems, at small or large scales. Something is wrong. (p. 410) 

After considering several modest “fixes” for AI and Alife (e.g., incorrect parameters, lack of computing power, lack of complexity in models), Brooks turns to a more challenging diagnosis: “we might be missing something fundamental and currently unimagined in our models of biology” (p. 410). He argues: 

We would then need to find new ways of thinking about living systems to make any progress, and this will be much more disruptive to all biology. ... So what might be the nature of this unimagined feature of life? One possibility is that some aspect of living systems is invisible to us right now. The current scientific view of living things is that they are machines whose components are biomolecules. It is not completely impossible that we might discover some new properties of biomolecules or some new ingredient. One might imagine something on a par with the discovery of X-rays a century ago, which eventually led to our still-evolving understanding of quantum mechanics. Relativity was the other such discovery of the twentieth century, and had a similarly disruptive impact on the basic understanding of physics. Some similar discovery might rock our understanding of the basis of living systems. (p. 410) 