On Wednesday evening, March 20, 2013,1 Paul Davies2 — theoretical physicist, cosmologist, astrobiologist and best-selling author — spoke at the Wisconsin Institute for Discovery at the University of Wisconsin-Madison.3
Davies’ presentation on The Origin of Life moved beyond the traditional discussion and explored the deep conceptual mismatch between the realms of physics and chemistry (which are cast in the language of matter, energy and forces) and the realm of biology (which is described in the informational terms of genetic instructions, signals and codes). According to Davies, research to-date has focused on “the hardware” — the physical components and processes involved in the emergence of life. As an alternate approach, Davies outlined a “software” perspective grounded in the organization and management of information.
What We Know (and Don’t Know)
The first portion of Davies’ presentation assessed what we currently know and understand about the origin of life on Earth. There are three big questions around the origin of life:
- When — In the case of when life evolved on Earth, Davies explained, we actually have a pretty good idea.
- Where — Regarding where life first arose on Earth, we are less certain, but have some good candidate locations/environments.
- How — How life arose is the big unknown, Davies said, and we really haven’t made much progress on the mechanisms behind the emergence of life since the Miller-Urey experiment in 1953.
The question everyone asks today about life elsewhere in the universe is, “How likely is it that life arose beyond Earth?” As Davies explained, “since we don’t know the process (by which life arose on Earth), we can’t estimate the odds.” With that realization, Davies moved into the second portion of his presentation — examining what can we do to better understand that process by which life arose on Earth.
Information Management and the Emergence of Life
In order to uncover and understand the process behind the emergence of life on Earth, Davies currently is forging connections between the world of particles (physics and chemistry ) and the world of information (biology). While life may be built with chemical components, Davies explained, the process behind the beginning of life is not chemistry, but information management. In that sense, the origin of life is not really a question of how did the hardware (cells and their components) arise, but how did the software (DNA and the genetic code) arise. As Davies frames the question, how did chemistry — the hardware of life — produce software?
Davies looked to the groundbreaking work of John Von Neumann4 on how life resembles a mechanical constructor. Von Neumann set out the logical structure required for a self-reproducing automaton to replicate both its hardware and software. (At the time, this work by Von Neumann was considered merely a curiosity.) What is clear today is that the dynamics of information flow utilize elements that are independent of the specific hardware supporting the information. And although this information independence has been applied by others to areas within biology, Davies is among the first to apply it to the question of how life actually began.
|Trivial Self-Replication:||Non-Trivial Self-Replication:|
Building on Von Neumann’s perspective of the role of information, Davies asserted that life’s genetic code communicates via mathematics, not chemistry. DNA only does “stuff” when inserted into a larger context (ie, cell machinery).
Once in such a context, information not only manifests in a bottom-up fashion (progressing from an instruction to manufacture a specific protein to the resultant overall organism), but also in a bottom-down fashion (where information at the global level of the organism is passed back down to the genes — in a form of feedback loop — setting additional constraints on the express of a given gene). An example of this bottom-down information flow is Epigenetics, where the presence of an electrical field can alter — or turn on/off — a gene’s expression.
During 2012, Davies and Physicist/Astrobiologist Sara Walker5 described this information management perspective of the process in “The Algorithmic Origins of Life” in Interface, The Journal of the Royal Society.
Although we may never know the specific details of how life arose on Earth, understanding the broad strokes may lead to answers (or a better understanding of) other big related questions. Does life readily emerge whenever the right (Earth-like?) conditions exist, or was the emergence of life on Earth merely a bizarre statistical fluke? Could life have started more than once on Earth? Could there be an alternate “shadow” biosphere (or biospheres) on Earth beyond the life we recognize?6 And ultimately, is life likely elsewhere in the universe, or are we alone? Davies makes the case that taking a software perspective offers a viable path for examining these questions.
- Apologies for the delay posting this article! [↩]
- Davies currently is Director of the “Beyond Center for Fundamental Concepts in Science” and co-Director of the Cosmology Initiative, both at Arizona State University. Previously he held academic appointments at the Universities of Cambridge, London and Newcastle upon Tyne in the UK, before moving to Australia in 1990, initially as Professor of Mathematical Physics at The University of Adelaide. Later he helped found the Australian Centre for Astrobiology. [↩]
- Paul Davies talk was part of The Center for Complexity and Collective Computation’s (C4) “John von Neumann Public Lecture Series in Complexity and Computation.” [↩]
- Von Neumann is credited with such varied ideas as Mutually Assured Destruction (in nuclear defense) to self-replicating machines. [↩]
- Walker works with Davies at the “Beyond Center for Fundamental Concepts in Science” at Arizona State University. [↩]
- Davies considers the possibility of a shadow biosphere intriguing and suggests an effort to search for one. [↩]