Firstly, this is not an academic matter.
Biology, as George Wald had said, was a unique science because it could not define its subject matter. Nobody has a definition for life.Nobody knows what it is, really. The old definitions an organism that showed ingestion, excretion, metabolism, reproduction, and so on are worthless. One could always find exceptions.
Is energy conversion the hallmark of life??
All living organisms in some way took in energy as food, or sunlight and converted it to
another form of energy, and put it to use.(Viruses were the exception to this rule)Let’s consider three objects: a swatch of black cloth, a watch,and a piece of granite. We can argue that these three are living things.
Let’s place the black cloth in the sunlight; it becomes warm. This is an example of energy
conversion-radiant energy to heat.It can be objected that this is merely passive energy absorption, not conversion. It can also be objected that the conversion, if it can be called that, is not purposeful. It serves no function.But how do you know it is not purposeful?
Let’s turn towards the watch. The radium dial glows in the dark. Decay takes place, and light is being produced.It can be argued that this is merely a release of potential energy held in unstable electron levels. But it’s confusing; I hope I am making a point.
Finally, let’s come to the granite. It is alive. It is living, breathing,walking, and talking. Only we cannot see it, because it is happening too slowly. Rock has a lifespan of three billion years. We have a lifespan of sixty or seventy years. We cannot see what is happening to this rock for the same reason that we cannot make out the tune on a record being played at the rate of one revolution every century. And the rock, for its part, is not even aware of our existence because we are alive for only a brief instant of its lifespan. To it, we are like flashes in the dark.
