Cletus the Foetus ♥'s puddles
Today, on my way to school, I was stopped at a corner, waiting for my light to change. The night had been cold, and yesterday's rain had frozen, but now that the sun was out everything was melting.
At my feet, a puddle was growing, fed by runoff coming from the Esso parking lot which lies only a couple of meters away, slightly up a hill.
I thought to myself, "If that puddle gets big enough, surface tension and the irregularity of the pavement are going to split it into two baby puddles. That's like asexual reproduction. And it's feeding from that runoff. So is the puddle alive?"
This, of course, led to hours of fascinating debate in the catbox, but there were too many issues that we were unable to resolve. So I went off in search of a textbook definition of life (as a biological process) by which I could determine whether a puddle is alive. After some searching around on the internet, I discovered that there isn't a whole lot of consistency in the definition of "life." So I've culled what I could.
–1:–
A Life Form is an organic whole.
The first thing to keep in mind is that a living being is organic. This philosophical term means that the entity in question is, as a whole, more than simply the sum of its parts. Modern computer science and artificial intelligence research use a similar concept: emergent phenomena. Life is a Gestalt, a holistic or synergistic or transcendental phenomenon. Organicism is a category of life.
–2:–
A Life Form can reproduce.
A living being can generate another, like being (another organic whole). Known life forms have various ways of doing this, including budding or other forms of asexual reproduction, as well as sexual reproduction (which includes endogamy as well as exogamy). In effect, if an organic whole can so much as split into two new wholes which have the same definitive nature as the parent, the entity has reproduced.
–3:–
A Life Form has metabolism.
Some scientists emphasize the conversion of energy from one form to another. Considered loosely, however, metabolism means the incorporation of outside matter into the form's mass. This may be a prelude to reproduction, adaptation, movement, or simply maintenance.
–4:–
A Life Form responds.
A living being can respond to its environment in certain ways. This can include locomotion, growth against force, homeostasis, whatever. The point is that the body undergoes some sort of motion as a result of something that happens in the environment but which is more than simply the application of brute force on the thing.
In addition to these fundamental or essential characteristics, most life (as we commonly recognize) exhibit certain tendencies. Most living things have highly complex forms, composed of many chemicals which interact in fairly regular ways. They also tend to regulate their own bodies (homeostasis). Metabolism generally involves the