20090511

Life?

This is one of those things that every living entity on this planet has in common. Yet we seem to be at a loss when confronted with the question, “What is life?”. I mean, it is not like a non-living entity would walk up to one of us ask with a tap on the shoulder, “Er... excuse me, but I couldn't help but notice that you have life, and I was wondering if you could enlighten me as to what life is”.

Though that situation may never arise, it would do us well to attempt an answer. It would do us well as it would enable us to see life from a new perspective. Maybe we could notice something that had remained unnoticed before. Then there would be many fundamentally different explanations and theories, we could debate them, these theories could grow in magnitude and become religions and we could go to war over the matter of “Which one of us is right?”.

On a more serious note, the answer to “What is life?” or the method of arriving at a suitable answer to it would enable us to analyze life in detail and answer many personal questions. For example, I have always asked myself why it is that we consider our kind of life the only kind of life there is (you know, carbon based, oxygen breathing organisms). Apparently the oxygen breathing part is not a sufficient condition for life as is evident thanks to the many anaerobic bacteria that have been found. So is reproduction.

No one would consider a eunuch to be a non living entity. It is no secret that eunuchs are incapable of reproduction; yet we count them under the living. Ergo reproduction too seems to be a necessary but not sufficient condition for life. So what are the sufficient conditions for life? What condition or group of conditions, which when present guarantee the presence of life?

From my currently limited perspective, I can see one thing. Living things are born, they lead a “life” and then they die; they have a life cycle. They are self sustaining; either they consume certain resources from their surroundings to ensure their own existence or they have all the resources they need for existence within themselves and they die when the resources within themselves are depleted. A partial example for the latter would be insects in the pupa state, hibernating animals, etc.

Life cycles have been ascribed for seemingly inanimate objects too. Stars seem to have a life cycle. They are said to be “born” in a nebula. They live out their lives by running nuclear fusion reactors, first by fusing hydrogen into helium, helium into carbon, carbon into neon, neon into silicon, and finally silicon into Iron. Finally they reach the stage where their core is made up of Iron or some other heavy metal, which they cannot fuse into something heavier profitably, they collapse on themselves and their “life”ends. Their “death” results in either a white dwarf or a neutron star or a black hole (depending on the size of the original star subject to the Chandrasekhar Limit).

If we think of birth as simply a kind of creation and death as simply a kind of destruction, everything around us seems to have its own cycle of creation and destruction. Therefore it does not seem too big a stretch to try and ascribe life to everything. Even man-made objects; tables for example. Tables are created (birth), they serve their purpose which is to say that they support many things on their surfaces, they get damaged and we repair them(life), they eventually fall into disrepair and we discard them, then they are taken apart. Their useful parts are recycled, their combustible parts are incinerated and the rest are discarded as waste (death). This does not seem too big a stretch.

Many living things appear inanimate when observed for just an instant. Sure when observed for prolonged periods of time we can see evidence that suggests growth, self repair and so on. My point being this: what gives us the right to classify anything other than ourselves as living or non living? There are so many things we do not know. The extent of our knowledge of the universe is grossly limited. We do not even know everything about ourselves. We still do not completely understand the workings of our own brain. We still do not know why each and every single strand of DNA on earth is a left handed helix. Well as far as we know there is no physical, structural, functional or chemical explanation for why there do not exist any right handed DNA helices. The only conclusion I can draw from that is that there seems to be some way in which right handed helices are deficient, but we do not know enough to ascertain for ourselves what that is.

When there are such serious lacunae in our knowledge; why do we consider our definition of “life” so true? It is but an assumption. An assumption that we have made based on our limited knowledge which is based on our limited view of the universe. For all you know, some time in the future, what we consider to be nonliving may very well turn out to be a living entity.