# The Nature and Origin of Life Traditional definitions of life have focused on several important characteristics of living things. - Replication (inheritance and transmission to progeny) - Variation (random changes with differing reproductive success) - Metabolism (harvesting energy and matter from the environment) - Encapsulation (membrane enclosure of vital elements) - Homeostasis (maintaining a balance of energy and matter in and out of each cell) - Growth (from a single eukaryotic cell to maturity and death, bacteria simply divide) - Signaling (between cells and cellular components - neurotransmitters, hormones, pheromones. etc.) NASA offered a simple definition of life as "A self-sustaining chemical system capable of Darwinian evolution." In recent decades, inspired by comparisons with modern digital computers, scientists and philosophers have identified additional characteristics they regard as fundamental to life. Some thinkers single out one or two of these characteristics and then claim they have discovered the fundamental nature of life. Attempts to find the origin of life in the properties of chemical systems have defined a number of these "essential" defining characteristics... - Auto-catalytic processes (cf., [Melvin Calvin](https://www.informationphilosopher.com/solutions/scientists/calvin/), [Manfred Eigen](https://www.informationphilosopher.com/solutions/scientists/eigen/), [Terrence Deacon](https://www.informationphilosopher.com/solutions/scientists/deacon/) - Self-organization (cf., _autopoiesis_, [Francisco Varela](https://www.informationphilosopher.com/solutions/scientists/varela/), [Humberto Maturana](https://www.informationphilosopher.com/solutions/scientists/maturana/)) - Complexity ([Harold Morowitz](https://www.informationphilosopher.com/solutions/scientists/morowitz/), [Ilya Prigogine](https://www.informationphilosopher.com/solutions/scientists/prigogine/)) - Complex Adaptive Systems ([Stuart Kauffman](https://www.informationphilosopher.com/solutions/scientists/kauffman/), _[Santa Fe Institute](https://santafe.edu/)_) - Emergence (e.g., order out of chaos, [Ilya Prigogine](https://www.informationphilosopher.com/solutions/scientists/prigogine/)) - Nonlinearity, Nonequilibrium ([Ilya Prigogine](https://www.informationphilosopher.com/solutions/scientists/prigogine/) ) Living things exhibit all these characteristics, but none of them explains everything going on at the level of atoms and molecules. Prigogine is perhaps the most famous name in [chaos theory](https://www.informationphilosopher.com/freedom/chaos.html) and [complexity theory](https://www.informationphilosopher.com/knowledge/complexity.html). Although he made very few original contributions to these fields, he is famous for them, nevertheless. His work, especially his 1984 book written with [Isabel Stengers](https://www.informationphilosopher.com/solutions/philosophers/stengers/), _[Order Out Of Chaos](https://www.amazon.com/Order-Out-Chaos-Ilya-Prigogine/dp/0553343637/)_, is a major reference today for popular concepts like "self-organizing, "complex systems," "bifurcation points," "non-linearity,", "attractors," "symmetry breaking," "morphogenesis," "autocatalytic," "constraint," and of course "irreversibility," although none of these terms is originally Prigogine's. The name "dissipative structures" and perhaps the phrase "far from equilibrium" belong to Prigogine, but the thermodynamic concepts essential to understanding life were already in [Boltzmann](https://www.informationphilosopher.com/solutions/scientists/boltzmann/), [Bertalanffy](https://www.informationphilosopher.com/solutions/scientists/bertalanffy/), and [Schrödinger](https://www.informationphilosopher.com/solutions/scientists/schrodinger/), and perhaps many others. ## How Information Creation Explains Life - A place is required in the universe with a flow of energy of low entropy from a _source_ to a _sink_. A local pocket of "negative" entropy can form [information structures](https://www.informationphilosopher.com/introduction/physics/). - For example, the stream of radiation from the Sun retains its high color temperature but has a low equilibrium energy temperature at the Earth distance. The Sun is the _source_. The Earth equilibrates that radiation to the average Earth temperature. The _sink_ is the dark night sky on the side opposite the Sun. - Another high temperature _source_ is volcanism from the slowly cooling Earth interior. The _sink_ is the cooler ocean water. - [Creation](https://www.informationphilosopher.com/introduction/creation/) of a genuinely new information structure requires multiple possible outcomes. At a minimum, the creation may succeed or fail. As [Claude Shannon](https://www.informationphilosopher.com/solutions/scientists/shannon/) showed, if there is only one possible outcome, that outcome is [determined](https://www.informationphilosopher.com/freedom/determinism.html). Novelty requires multiple outcome [possibilities](https://www.informationphilosopher.com/freedom/possibiities.html). Without [alternative possibilities](https://www.informationphilosopher.com/freedom/alternative_possibiities.html), there is no _new information_. - At the atomic level, whether elements bond is a probabilistic quantum event. If they do bond, the binding energy must be carried away to satisfy the second law of thermodynamics. The bonded elements are lower entropy, but overall total entropy always increases. - The new information structure has more order, decreasing entropy, so the energy with high entropy carried away satisfies the requirement that the overall entropy increases. Again, if the positive entropy needed to satisfy the second law is not carried away, a new information structure is not possible. - All information creating events have this two-step structure: first quantum processes generate multiple [possibilities](https://www.informationphilosopher.com/freedom/possibiities.html) with _in principle_ calculable [probabilities](https://www.informationphilosopher.com/freedom/probability.html); second, if a low-entropy information structure is created, the high "positive" entropy energy carried away must exceed the low "negative" entropy gain. - Many transient structures may form for a moment, for example hydrogen atoms in the early universe, but they are quickly destroyed if the ionizing photons can not be radiated away from the proton and electron. - Atoms, molecules, planets, stars, and galaxies are all new information structures. But they are _passive_ structures. - Living information structures are _active_, communicating between their component parts, and communicating with other living things and their environments. - Communicating means _signaling_, sending and receiving information between cells and between cellular components. - Living things actively use information to manage their replication. - Feedback from their component parts allows regulation of their _homeostasis_. - Information coming in from outside makes them _aware_ of their surroundings. In higher animals we call this [consciousness](https://www.informationphilosopher.com/problems/consciousness/). - The broadest possible _definition of life_ may be to regard living things as _forms_ through which matter and energy flows, with their _active_information structures managing that flow. - Those matter and energy flows are of course also information flows. - The information content of a living thing is its [metaphysical essence](http://metaphysicist.com/), because the particular matter and energy are mere transients through the largely unchanging _form_, its "[identity](http://metaphysicist.com/problems/identity/)." - _Information is neither matter nor energy, though it needs matter to be embodied and energy to communicate with other information structures._ - _Physicists_ think that the material universe obeys "laws of nature" that they have discovered. Some think these laws [determine](https://www.informationphilosopher.com/freedom/determinism.html) everything that happens. Others think the control is only statistical. But the "supervening" laws of chemistry and biology can not be [reduced](https://www.informationphilosopher.com/knowledge/reductionism.html) to bottom-up control by our component atoms. - _Chemists_ see life as simply [complex](https://www.informationphilosopher.com/freedom/complexity.html) chemical processes, enabled by some molecules that catalyze reactions that normally do not occur in equilibrium conditions. [Some chemists](https://www.informationphilosopher.com/solutions/scientists/cashmore/) think that the information in any particular assembly of molecules is the same as any other with the same molecules. A living thing is just "a bag of chemicals" or a [huge molecule](http://www.eoht.info/)." The evolution of living things cannot be reduced to chemical evolution. - _Biologists_ have traditionally denied that "information" is relevant for understanding life, though this is changing with the study of cellular signaling. Concepts like [information](https://www.informationphilosopher.com/introduction/information/), [knowledge](https://www.informationphilosopher.com/knowledge/), [meaning](https://www.informationphilosopher.com/knowledge/meaning/), and [purpose](https://www.informationphilosopher.com/mind/purpose/) are what philosophers of biology describe as "category errors." Biologists who accept that biology reduces to chemistry, which reduces to physics, are nervous about claims of the "[emergence](https://www.informationphilosopher.com/knowledge/emergence.html)" of "holistic" or "idealistic" properties. - All three of these kinds of scientists are often conflicted about the second law of thermodynamics and its derivation from statistical mechanics. - Cosmologists too are often confused about the second law. Order cannot arise out of chaos just because the laws of dynamics are nonlinear, reactions are auto-catalytic, or system structures are complex. - Information philosophy has shown that every bit of [information creation](https://www.informationphilosopher.com/introduction/creation/) in the universe is a two-step process that ends with positive entropy leaving the new information structure and starts with [indeterministic](https://www.informationphilosopher.com/freedom/indeterminism.html) quantum-mechanical generation of [alternative possibilities](https://www.informationphilosopher.com/freedom/alternative_possibilities.html). - These possibilities are only possible because of the expansion of the universe! In a _closed_ finite system, entropy always increases everywhere. In a _closed_ system in equilibrium, there is no place for positive entropy to go. - But the universe is not a _closed_ system. It is in a dynamic state of expansion that is moving away from thermodynamic equilibrium faster than entropic processes can keep up, as first suggested by [Arthur Stanley Eddington](https://www.informationphilosopher.com/solutions/scientists/eddington/) in 1935, who said > The expansion of the universe creates new possibilities of distribution faster than the atoms can work through them, and there is no longer any likelihood of a particular distribution being repeated. > > > (_New Pathways in Science_, 1935, p. 66) - The maximum possible entropy is increasing much faster than the actual increase in entropy. The difference between the maximum possible entropy and the actual entropy is potential information, as shown graphically in the 1970's by my colleague in the Harvard astronomy department [David Layzer](https://www.informationphilosopher.com/solutions/scientists/layzer/).  - Pockets of low or "negative" entropy are therefore possible. Locally, an information structure can have less entropy and more information, even though the global entropy has gone up. When a hydrogen atom forms from a proton and electron, its entropy per particle is lower. When gravitational forces pull clouds of matter together to form a star, the work performed by gravity heats up the matter. If that heat could not be radiated away from the new star, it would stop collapsing. The expanding space between all objects provides the thermodynamic sink for the positive global entropy. - Philosophers of Mind can not explain how [mind](https://www.informationphilosopher.com/mind/), with its _immaterial_ "ideas," can be _[reduced](https://www.informationphilosopher.com/knowlede/reductionism.html)_ to "materialist" biology, which is then _reduced_ to chemistry, which is _reduced_ to physics. Many accept a form of "[pan-psychism](https://www.informationphilosopher.com/mind/panpsychism/)," that mind must be a fundamentally intrinsic property of matter. They think that mind cannot possibly have [emerged](https://www.informationphilosopher.com/knowledge/emergence.html) from matter. Information philosophy shows them to be [wrong](https://www.informationphilosopher.com/mind/). Minds are [created](https://www.informationphilosopher.com/imtroduction/creation/).