Life, a simple word with a complex meaning. In the context of individual human life, life could be defined as ones physical and mental interactions with their environment from birth till death. In astrobiology, this type of life is irrelevant because they are trying to discover the possibilities of life outside our planet. Then what is the definition of life in the scientific context? First and foremost one must be careful with their vocabulary. To some, a definition is definite, meaning the word is what it is, as an example a table. Is life tangible or intangible? In science no theory is one-hundred percent definite or known. With advancements of technology and new discoveries a theory could be solid one day a dead the next. With the intangibility and ever changing way of life, maybe the best way to “define” life is to present it as a theory or group of theories that can constantly change and not stay finite.
A couple theories for can be found in the paper “Defining Life” Benner S. One theory is the “NASA definition of life: life is a self-sustaining chemical system capable of Darwin evolution. According to this definition human beings would be considered living. The human species has been evolving since we lucked out with our conditions for life. If these conditions did not arise in the first place and our atmosphere was comparative to Neptune, Human life as we know it could not exist! Another lucky trait humans where blessed with is that the species could be considered generalist, or toll makers versus specialists who are good at one thing. During the ice age and rapid climate change this played a key role to our survival. Now our tools our advancing parallel to our own evolution. This has paved the way for our species to have the potential to become supra-Darwinistic where we can create our own path so to speak and completely side step natural selection. If we become supra-Darwinistic are we no longer living according to NASA’s definition? And when we reach that point and we are not considered living where we ever alive in the first place? This is one example of how life theories are toyed with in the minds of humans.
In contrast to the theory found in Benner’s paper one only needs to read Walker’s “The algorithmic origins of life.” In this paper life can be theorized as the flow, translation, and storage of information, being stored and used for specific situations. One can relate the evolution of life to the history of avionics. Life started as RNA or an analogue plane controlled by a joy stick. The RNA (joy stick) move and the rudders moved. Then Darwin evolution (or technology advancement) introduced the computer to the plane. This would demonstrate life now demonstrating DNA-protein combination with RNA still playing a role but not THE role of life. Technology is still advancing and one day avionics may be all computerized. This could represent supra-Darwinism. With this approach supra-Darwinism can still exchange, understand, store, and use information for specific tasks; thus a supra-Darwistic being can still be considered life.
Why is this idea of supra-Darwinism important? In the context of astrobiology and finding life on other planets it would help to know what we are looking for. Maybe planets are advanced and only supra-Darwinistic life only exists and we don’t understand it. Or maybe the definition of life is not as important in trying to find life as is the conditions to contain such life. In conclusion this is what makes “life” science fun, not knowing what it is but trying to find its meaning.
I like how this post talks about different interpretations for the definition of life, and compares and contrasts their distinct differences. This post could use the addition of discussing how our current definition of life could be updated if organisms outside of our solar system were found to exhibit qualities of living thing, but not conform to our present definition of life.