A universal definition of life
Ruiz-Mirazo K, Pereto J, and Moreno A. (2004) A Universal Definition of Life: Autonomy and Open-ended Evolution. Origins of Life and Evolution of Biospheres 34(3):323-46. Image:2004.Ruiz-Mirazo.pdf
- We propose to define universally living beings as autonomous systems with open-ended evolution capacities, and we claim that all such systems must have:
- a semi-permeable active boundary (membrane);
- an energy transduction apparatus (set of energy currencies);
- and, at least, two types of functionally interdependent macromolecular components (catalysts and records).
What do you think of these claims? The paper?
- Obviously, I like the paper since I chose it. In the Quantum Coreworld lifeforms can begin with a simple energy transduction apparatus, a very primitive boundary and the possibility of separate catalysts/records. But the locality of (3D) space also seems to be essential for "open-ended" evolution. None of these, however, are "provably" essential and there might be other features that are essential... How can we know? --ASW 10:00, 2 Aug 2005 (EDT)
- Not an original thought (Varela?), but it seems common sense that you can usually tell whether something's alive by looking at it for a little while. You don't have to know anything about evolution. So a definition that appeals to evolution to define life doesn't reflect the usual meaning of the word. How will it help you to have a definition, anyhow? --Jonathan Rees 11:30am EDT 2 Aug 05
- many people have come to think that the idea of evolution must be part of the definition of life. A flame is very complex (in the information theory sense) and it replicates. A mule is also complex but doesn't replicate at all. Are flames alive? Are mules? (And going further) are viruses? Mules, viruses and humans are interrelated by evolution. Depending on your preferences, I think it's fair to say that they are alive. Flames are not interrelated by evolution (with other living things) so they are not alive despite being complex and self-replicating. What do you think? --ASW 12:01, 2 Aug 2005 (EDT)
- Maybe flames can "evolve", i.e. take on heritable properties in response to a changing environment; e.g. encountering a series of fuels with different upper/lower [flammability limits]. Flames may have high "entropy" but not high "complexity" in the sense below. (Maybe someone could provide an open-source version of the "Statistical Complexity" calculations for the well-defined examples below and/or ways to estimate it for more interesting scenarios like flames and viruses).J. P. Crutchfield and K. Young, [Inferring Statistical Complexity], Physical Review Letters 63 (1989) 105-108. J. P. Crutchfield and K. Young, Computation at the Onset of Chaos, in Entropy, Complexity, and Physics of Information, W. Zurek, editor, SFI Studies in the Sciences of Complexity, VIII, Addison-Wesley, Reading, Massachusetts (1990) 223-269.--gmc 5-Aug-2005
- Flames might evolve in a limited way but the "parts" of a flame are so simple that their reuse in living things is very limited. (While the parts of a mule or a virus get much more interesting reuse.) Can any of this discussion be made quantitative? It's not easy... --ASW 10:53, 16 Aug 2005 (EDT)
- http://cscs.umich.edu/~crshalizi/notebooks/complexity-measures.html Gives updated references for "Statistical Complexity", maybe, Cosma would be interested in speaking at ALife Boston the next time he happens to be in Boston... --ASW 08:15, 13 Aug 2005 (EDT)
- add your thoughts here
Does God Play Dice? Divine Providence and Chance
Elizabeth SJ (1996) Does God Play Dice? Divine Providence and Chance. THEOLOGICAL STUDIES 56:3-18. http://www.aaas.org/spp/dser/evolution/perspectives/johnson.shtml
- In every age theology interacts directly or indirectly with the view of the world prevalent in its culture, including knowledge of the world gained through observation or experimental means. Although certain encounters of theology with this "scientific" intelligence have been shot through with hostility, the history of theology may also be read to disclose how dialogue with technically learned insights about the World has enkindled new religious wisdom, inspired appealing metaphors, and provided a context for new interpretation of religious tradition. (1) In any event, theology's interaction with science is essential to make religious faith both credible and relevant within a particular generation's view of the world and how it works.
Some thoughts from Tom Lord
There are two (related) things I can add but they aren't really polished yet.
The first is on the nature of randomness as it might relate to mind, human meaning, free-will and so forth. Elizabeth Johnson (the link above) seems fuzzy about that connection. Randomness is randomness, as far as she is concerned and that is that. She basis her metaphysical analyses on that. (She is also a little centric about a monotheistic interpretation of God and that seems a needless limitation.)
I'm making a more specific conjecture about the math -- one which I'm personally pretty confident of but not prepared enough yet in the math to prove it.
My more specific conjecture is that in the material universe we have a discrete, countable set of random events but that there exist mathematical models in which these could be produced by non-random processes operating on sets of greater cardinality. We have no physics, no evidence that any material thing exists whose state has a structure for which higher-cardinality sets are the right model -- there isn't that much "stuff". Yet the best theories and evidence we have explicitly fail to rule out the possibility -- seem only to say "it could be true, but you can't prove it by experiment".
That's an odd juncture for science to reach: scientific proof that there exists a question about nature which science can not answer. A scientific result seems to be: the metaphysical might exist and its possible mathematical structures are open to contemplation.
My second addition is that the nature of Qualia (the conscious experience, the mind, our subjectivity) seems to me to be clearly available for scientific study though through the limited mechanism of collecting reports from people about what it's like. Old canards like "how do I know that the red you see is the same as the red I see" aren't really an obstacle. Instead, we have thousands of years of literature describing a curiously bounded subjective experience within which much information about the state of our brain is simultaneously present. It is in the context of this subjective phenomenon that we grasp at concepts like meaning, feeling, and will. There is a certain indivisibility to this subjective experience. Physics famously and recently gives us a model of material processes containing elements which are arbitrarily information rich and indivisible (e.g., the state of a quantum computer).
I'm not the first to ask, I'm sure, whether our subjectivity is exactly an example of such physical phenomenon.
Synthesizing these two things (the scientific possibility of a non-random, transfinite metaphysics; the possibility of the mind as a unitary entity in which metaphysical processes may play a role) we arrive at a wealth of theological implications and apparently permanent uncertainties.
Are our minds uniquely identified with metaphysical souls in communication with a singular metaphysical god? I suspect we'll scientifically prove that it is possible but not provable.
Are we monadic souls under a pantheon? Same answer.
Are we animistic spirits? Does a stream or a vacuum tube have a soul of its own? Same answer.
Is the universe in fact meaningless and devoid of any metaphysical connection? Same answer.
A curious problem: in this (sketched) model -- "unprovable" is not the same thing as "not subjectively perceivable". If we are, indeed, beings with a metaphysical component -- perhaps that component participates in a perception of the overall metaphysical nature of the world. In Judeo-Christian terms (not the only possibility) -- God might be a meaningful player in our lives even if the truth of this relationship is beyond what science can ever hope to prove.
Moral consequences follow from this, one in particular:
People are entitled to hold and share metaphysical opinions in the same way the are entitled to create and share art. Yet at the same time, any doctrinally-based religious practice based on the explicit or implicit premise of spreading any kind of "enlightenment" on metaphysical topics, including if not especially those based on communicating revealed truths -- is certain to have an objectively random, meaningless result (were it otherwise, the metaphysical would be scientifically provable).
The predictable consequences of such behaviors (social control, excessive and unhealthy social coherence, the spread of intolerance and hatred, that kind of thing) are the ethical effects on which such behaviors must be critically evaluated.
- add your thoughts here