X: How can you determine the philosophical temperament of medical students?
Y: Ask them to define life.
Y: Ask them to define life.
Most people have a distinct notion of "living" and "non-living", the two being separated by a wide chasm, a binary situation of 0 or 1. Furthermore, under the influence of the representational view of language, they think of "Life" as a noun representing some sort of an entity, which makes the living living. However, both of these notions turn out to inadequate, if we consider life at the molecular level, and take into account the non-representational view of language (such as that given by Wittgenstein). Let us consider this issue in a semi-Socratic fashion.
At the level of multicellular organisms, it is easier to determine what is living: there is a set of chracteristics like nutrition, growth, metabolism, homeostasis, adaptation, reproduction, locomotion, which an organism exhibits. If we go one step lower to unicellular organisms, many of these characteristics vanish: for instance, there is no nervous system, so all sorts of cognitive functions are ruled out. There is no circulatory system, only a movement of cytoplasm within the cell. Nutrition, gaseous exchange and excretion merge into one pathway. However, since most of the characteristics are still present in some manner, therefore a unicellular organism is declared living. Let's go a step even lower: consider viruses. These have a very simple structure, consisting of only protein and nucleic acid. They show almost none of the characteristics we see in multicellular organisms, except that they can reproduce (make copies of themselves) and can show adaptation (through genetic variation). There is no metabolism of any sort. When asked the question "Is virus living?" most people show only a slight hesitancy before declaring that virus is living because it can reproduce. Let's go down further: consider prions. These are infectious particles consisting of proteins only, and yet they can reproduce. When asked "Are prions living?" most people would say no. They give two reasons for this: 1) prions make copies of themselves, yes, but they do so through indirect means 2) prions don't have nucleic acid. The first reason is somewhat invalid, because viruses too replicate through an indirect means. If we accept reason no 2, it implies that it is nucleic acid what makes an organism "living". But a nucleic acid by itself is not living; it is just a molecule. So, if nucleic acid is non-living, and proteins are non-living, then how does the combination of a nucleic acid and protein become living, since nothing extra has been added? I am yet to hear a satisfactory answer to this question. [Don't even begin to think that viruses have a "soul" which makes them living. It is too absurd. And besides, we can create viruses artifically in the lab. So that means we can create "soul" too? Oh, here is another point. If we accept that viruses are "living", then it would mean that we can create "life", because we can create viruses artificially. J Craig Venter has already created the first synthetic bacterial genome. How far are we from creating the first synthetic bacterium?]
So, what am i trying to say by all this? My point is that "living" is just a description of characteristics that was applied to multicellular organisms. As microscopic organisms were discovered, this description became less and less valid, until arriving at the virus and prions, the description becomes meaningless; the word "living" becomes meaningless. The question "Is virus living?" is meaningless because it is trying to apply a description which was meant for a multicellular level at the molecular level. There is no well-defined distinction between "living" and "non-living" at the molecular; rather we see a gradual progression of accumulation of characteristics associated with multicellular organisms, with no distinct point being labelled 'life begins here'.
Similarly "Life" is just a word, an abstract noun; it's meaning is defined by its usage (non-representation linguistics). There is no metaphysical entity of any sort that it represents. Beyond linguistics, there is no such entity, of whatever ontological nature, as 'life'.