WHAT IS LIFE?
June 29 2009
This seems to be a simple enough question: what exactly constitutes the definition of 'life'?
Let us begin, at the beginning - as they say.
Life, according to scientists, begins at the cellular level. Thus, life begins with the cell's components. But why is that? According to biologists, for life to exist, there must be all or most of the following phenomenon: homeostasis, organization (ie. being unicellular or multicellular) metabolism, growth, adaptation, response to a stimuli, and reproduction.
Certainly, any cell exhibits these phenomenon, and so, the cell is classified as being 'alive'.
Yes, the cell contains the common consensus of what it is to be alive, but, in what way, is the cell alive?
According to Aristotle, there are three kinds of 'souls': the 'vegetative soul', which includes plants; the 'animal soul' and the 'rational soul', by which he meant us human beings. We have now introduced the concept of the 'soul' into the meaning of life.
Let us go back to our cell. It is alive. We know that the humble cell contains many units, which work in combination, to make the cell alive. Thus, both animal and plant cells have cytoplasm, a nucleus, mitochondrion, cell membranes and so on. The question now becomes this: are the constituents of the cell also alive, or do we have to see the cell alive, only when all of its parts work together, and therefore, the constituents of the cell itself, are not alive?
Here, we enter into murky waters - scientifically speaking.
Let us answer, that only the cell itself is alive - without getting involved with its constituents. What, exactly, makes it 'alive'? Because, as we have seen, the cell shows the attributes, we've discussed. But, don't the constituents of the cell, by the same bio-cellular logic, maintain the same properties? Don't they, too, metabolize, replicate, respond to stimuli (electrical and chemical) and so on? So, why aren't they given the living classification?
Let's delve deeper here.
Is the DNA alive? All of it, are parts of it? Which parts? What about the fundamental atoms and molecules, that are needed for life - such as oxygen, hydrogen, carbon, nitrogen and calcium - are they 'alive'? Are carbohydrates alive? Or lipids? Proteins?
Cellular biologist can be divided into Holists or Reductionists. Holists believe that 'life' is an emerging property, that emerges from the interactions of its constituent parts. The Reductions discards that theory, and believes the life exists at all levels of the cell.
It seems to me, that if we are going to talk about 'life' when discussing cells, then we must enter into the mystical realm. Why? Because, yes, the cell has the attributes that biologists give to what is necessary to be alive, but we still are nowhere nearer to an understanding of the meaning of 'life' is.
Is the cell conscious that it exists? Does it have any form or type of self-awareness? Obviously, we do not know, but the question does presuppose that life requires 'consciousness' or 'self awareness' - is that correct?
Let us look at a tree. All biologists will immediately tell us that the tree - indeed, any plant - is alive. And, yet, what puzzles me is that the tree is 'alive' only in the strictest sense of the mechanics of its biological functions.
What about our friend the German Shepherd dog? Obviously, he is alive and full of vitality and energy. Indeed, the Alsatian dogs have many characteristics that we humans have - such as showing affection, loyalty, obedience and listening to commands and orders.
Can we then say, that the German shepherd dog is far more 'alive' than the tree or flower?
And from that question, can we say that some creatures on our planet are 'more alive' than others?
Some scientists will object to our example, by arguing that it is we human beings who are being prejudicial by defining what defines as being 'more alive' than other creatures. Indeed, it seems that the more animals behave like us, or have our characteristics, the more we regard them to be that much more 'living' than, say a worm or bacteria. That is, as some scientists argue, simply untenable as a valid scientific argument.
There is no point in trying to argue which species or organism is 'more alive'; I say this, because you will simply end up going on a fast path to nowhere.
We can certainly discuss what consciousness has to do with the meaning of life, for in this sphere, we are on more solid ground. Let us go back to our tree and dog example. Obviously, the dog shows more signs of consciousness than does a tree. (Again, the only way I am going to accept that a tree has some level of consciousness, is if we enter the subject of mysticism, of which, I am no great believer in).
So, our question is this: is the dog 'more alive' than the tree, given the different consciousness levels?
If, by alive, we mean a creature that has more awareness to its surroundings, then, yes, the dog is certainly 'more alive' than the tree.
Therefore, the more an organism is aware of his/her/its surroundings and to its self, then the greater degree of life exists within that organism.
That is why, if we look at a person who is in a coma, we can say that biologically he is functioning like a plant would function. The comatose person's body is doing all the biological functions - except, that it has no consciousness. That is why, a comatose human is 'less alive' than a non-comatose person.
Ayad Izzet Gharbawi