Posted by: dacalu | 19 October 2015

Approaches to the Meaning of “Life”

This post is part of a series on what we want from definitions of life.  It stands alone, but if you want to see the whole series, it starts here.

I would like to suggest five prominent approaches to how we model life. I do not claim these five ways are exclusive or exhaustive. Rather they are five well worn paths that many have taken in search of the meaning of “life.” Specific models – such as Aristotle’s nutritive soul or Schrodinger’s delayed entropy – can be assessed by the work they do in each approach. Often they will have been designed with one approach in mind and be very successful in that way. Often they will then be appropriated by thinkers to do work in another approach – with mixed success.

Each of the approaches comes associated with a focusing question or two that highlights what I see as a central concern. I hope to better identify the place of these various approaches in specific conversations – for example scientific origin-of-life research or Catholic environmental ethics – as well as global conversations on the definition of life. I will return to these questions at the end with my own concerns – how to search for life in space and how to build healthy relationships between individuals and communities. First though, I hope to improve communication between a wide variety of people with a wide variety of concerns by talking about what may be at stake for them – and for all of us – as we discuss “life” together.

The Visceral Approach – Can I eat it? Can it eat me?

The first approach frames life in the context of opportunities and dangers. At the most basic level, we ask “can I eat it?” and “can it eat me?” Evolutionary theory suggests that we would have evolved very accurate, very fast heuristics for answering those two questions. In a more generic way, we often ask whether something is alive so that we can assess it as a threat or opportunity. In medicine, we want to eliminate potential pathogens. In international law, we want to preserve common goods. Alien-as-threat and alien-as-exploitable-resource are two of the most common tropes in science fiction and they often challenge us to think of species wide interests or even life-wide interests.

Using the visceral approach requires a reference subject and some statement of their interest. To whom is this life an opportunity or danger? A visceral approach research program would involve observing and anticipating outcomes. It must be subject dependent and prospective. When we speak of Extinction Level Events – such as a meteor impact killing off the dinosaurs – we think in terms of diminished life on Earth.

More approaches in the next post!



  1. […] alone, but if you want to see the whole series, it starts here. I’ve already spoken about visceral approaches to life – as threat and opportunity. Now we turn to broader and more abstract […]

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