The topic of the day is, what is life, what's living and what's not?

This is a topic, of importance philosophically, biologically, and even in computer science (Artificial Intelligence). I thought about this for some time, and I got the following candidates:

1) A thinking being is a living being.
2) A bunch of chemical reactions in a body, make it (by definition) a living being.
3) A creature with living and reproducing instincts, is a living being.

I thought about the first one for sometime, and it is very satisfying to accept it, as we, humans are thinking beings, and we regard ourselves as the "top of the progress", of the species evolution. Naturally, we would say, all beings evolved from brain-less to humans, so, a creature must have a brain, and humans are higher/better creatures since, we have brains.

But, this argument is not that convincing, if you look close. Dinosaurs, lived happily, for millions of years, even though their brains are of the size of a peanut (Don't believe the drama in Jurassic park, where Dino looks through the glass, twists the door-nob etc..., all without much acquiantence with them. I bet even our ancestor humans could not do that). And, many primitive organisms do not have any thinking unit, like no brain. Also, humans are able to outlive their critical period (you are into space now, if earth burns, lets go to moon), but, what if humans are not able to do so? If a big meteore had hit us, in 17th century, we would have vanished like Dinos. Let's say tomorrow, something un-containable happens to Earth, the species evolution might take an entirely different turn, than the "big brains" slogan. My point is that, evolution is not "progressing towards more brains", humans having brains is just like, dinos having big bodies. It helps to survive, that's all.

So after thinking that "thinking is not the one to think about" :-), we move ahead to the second one. This is more of a definition out of a theory book, in the sense, all cryptic stuff, nothing helps anyone to understand. Ok, but, let us see, what this offers us. "A bunch of chemical reactions....", I would say no. The best counter-example for this, is a virus. A virus, is it a living organism? People say yes, right. But, you know what that foul creature does?

If we go by this definition, viruses have the option of "suddenly starting to live", and to "die suddenly", not joking. A virus, by itself, does not do any 'bunch of chemical reactions...', it is just like a stone on Mars. The moment it finds a body that already does these, it attaches to it, and starts the 'chemical reactions'. And that is not all, after that body is savaged, it again returns to the 'stone on the Mars' look. So, is virus living or not? Well, it is somewhat in between... I am never a fan of such life-less definitions :-) myself, and, looks like this is a bad definition anyway.

Now comes the third one: 'Instinct means life', kind of definition. I actually, took a lot of time, to get to formulate this definition itself, and it looked so fundamental a statement, and it looked more and more profound, as I looked deeper into it. And, along with it, I think I discovered the meaning of evolution.

Darwin's theory is about "survival of the fittest, by natural selection". Let's focus on the 'survival of the fittest' part. The assumption here, is that, there is a population (of one species), with natural genetic variety, and nature randomly conducts a test on them, like a running race. Everybody runs, but 0nly some survive. And their genetic variety, moves ahead, and waits for the next test conducted by nature, at some random time in future.

I emboldened Everybody, in the previous paragraph. That is the underlying assumption in Darwin's theory. Let us understand this. Let's say, there is a population of humans, most of them short. Only some are tall. Then, there comes a huge flood, which submerges their habitat. The short fellows, can't survive (can't get their head up, lets say), even though they stand and try things like crazy. The tall fellows, also try to stand, and can breathe in the floods, which keep up for a week or so. Now, who survives, only the tall folks.

Let's say now that, the tall folks didn't want to survive, they didn't run the race. They just sat under trees, and waited till their lives are taken away by the flood. Now, who survives, no one, right. That is the point here. Everybody runs the race for their lives, when natures gives them a race to run. And, that is the assumption (most probably) in Darwin's theory. And that explains that, all creatures, along the way of evolution, had the instinct to survive, right from the protozoans, amoebas everything. Because, even if the first uni-cellular organism, did not try to survive, the evolution would not have moved an inch.

That clarifies our first presumption, that a creature needs to have 'the instinct to survive', in order to be living (more-or-less).

There is a small problem with this, which is, for evolution, we need this instinct, not for survival. So, if a species does not have this instinct, it is fine for that species, but no progress happens from that species (no evolution). Almost, there is no such thing, as a non-evolving-species in the world, anyway.

The second instinct, to reproduce, what about that? Is that necessary? Given that the life of a creature can be terminated (first instinct would not be possible without it), and given one population of one species always has finite genetic variety, it is not good for evolution, if all these things die, or they allow only 2-3 'natural selection' running races, since, only finite types of genetic variety exists, in the population. Instead, it is better, if the genetic variety has a way of changing, it helps nature to select using many types of races. If all these creatures reproduce, and generate a different group of genetic variety, that is good for evolution, in 2 ways. First, the first instinct is enforceable. Second, the genetic variety changes from generations to generations, enabling nature to conduct new types of tests on the species, which in turn, could cause new paths for evolution.

Thus, we conclude that the second instinct is also necessary for evolution. Looks like, this is the most fundamental thing, for a living creature. Any living creature (from which evolution is possible), needs to have the 'instinct to survive' and the 'instinct to reproduce'.

One might argue that, some creatures like Sheep, do not have the instinct to survive. One might say that, sheep, do follow the butcher, even if it sees the sheep before it, being killed by guillotine. Thus, one might say, it does not yield for it's life. But, that conclusion is wrong.

Sheep, cannot connect between the one before it, walking up to the guillotine, and its head getting chopped off. It's brain is not that great. It walks like a 3 year old, doing stuff, even after you warning him/her, it just can't connect the reason and effect, that's all. If you give it a near death experience with the guillotine, and do not actually kill it, the next time (or after several such attempts (on several such generations)), it develops the instinct to avoid guillotine. That's the beauty of instinct, you don't need to think.

Although, I want to mention one small counter-example to even this 'instinct is life' argument. There is some rodent species, which multiply like crazy. And, one fine day, they start their journey to the sea. This happens every year and, on the way, many of these get crushed by moving vehicles, some of them fall prey to predators etc... But, they continue their journey to the seas. And, what do they do, when they reach the shores? They jump into the sea, and die, not joking. And, this happens year by year, generations by generations, no change. That's the closest counter-example to this theory.

However, it is a very accurate commentary on the theory of evolution. I was delighted to find the roots of Darwin, who found the roots of mine.