What is Life?

Of all the questions that we can ask, perhaps there is no greater and more significant than this - to know what we are. Are we just physical bodies or do we have a soul?

The first step in any scientific approach to answering this question would be to observe all the variety of living things, then to define the characteristics that they all possess in common, and compare this to the characteristics of things we know to be dead and inanimate. This is the first and most fundamental exercise. Before jumping to any conclusions about what life is, we must first patiently gather our observations of the phenomena of life in it's varied forms. It is only upon a solid foundation of observations that we can base accurate inferences and deductions.

So we must begin by looking at living things in all their varied forms.

In the pages that follow, my aim is to catalogue each of the definitions of life proposed by scientists from the physical, biological and psychological sciences. Each definition holds a clue. After each definition is provided, I will look at why each scientist defined life so, and what it's implications are for the nature of the phenomenon we call life.

So here is the most interesting catalogue - embodying our best understanding of what we are.

A First Attempt

Twenty years ago I began to ponder this question. Walking alone under the stars, I wrestled with the issue. What is the perceived difference between a living thing and a dead or inanimate thing? What does a living thing do that a dead thing does not? My first thoughts hit upon the idea that a living thing appears to move of it's own accord, whilst a dead thing only moves when an external force acts upon it. This seems intuitively correct. An object that only moves when it is pushed or pulled from outside may be alive, but how would we know? However an object that moves independently of the causes operating in it's environment seems alive.

"The strings caused the puppet to move, and so we knew the puppet was not alive. Yet if a puppet did begin to move of it's own accord, without strings, then we might suspect that it had somehow come to life."

So here is a distinction that seems important. It may not be the only characteristic that defines life, but it seems to be at least one of the characteristics.

"Living things can act independently of their environment. They appear to initiate their own actions, rather than merely responding to external forces."

Lets examine this observation in more detail. What does it tell us about the nature of life?

Living things move of their own accord.

"A gentle breeze blew through the forest carrying dust and pollen on the wind, yet the fruit fly moved against the tide of the air. It zigzagged back and forth, battling the current in it's effort to reach the orchard. Unlike the dust driven by the wind, it seemed to have an autonomy of it's own."

"A bubble of air released from the bottom of a pond rises quickly to the surface. When an inverted glass is placed over it, the bubble still rises as before but remains trapped inside the glass. However a small frog departing from the bottom of a pond may rise to the surface for air. Finding it's path blocked by an inverted glass, the frog may change it's path of motion and descend again seeking the way of escape to circumvent the glass and reach the surface." 

(PS this is only a thought experiment. In no way would I ever obstruct any creature from finding air.)

Living things seem to initiate their own course of motion, acting independently of their environment to achieve a desired goal. Their independence always strikes us as a sign of life - as does their goal directed behaviour.

The Law of Cause and Effect

Science tells us that everything has a cause that precedes it. An event occurs because it is caused by some preceding event or condition, which in turn must be caused by some preceding event or condition ad infinitum. The preceding causes determine the proceeding effect. If it were not for this law then physical events would just pop out of nowhere with no reason for them to occur at one time or another. They would be un-hinged from time and their appearance would be a minor miracle. Thanks to the law of cause and effect, the inanimate world seems predictable with everything occupying it's correct place in the chain of causation.

So how do we account for living things that APPEAR to initiate their own motion. The frog is not forced to swim to the left or to the right. It might go either way. It appears to choose it's path. This is a characteristic of living things - that their actions appear to be self caused.

Whilst every inanimate object is tied in to a chain of causation, so that all of it's behaviour is explainable in terms of  prior causes, a living thing seems to cause its own behaviour without any sufficient preceding cause. For that reason it APPEARS to possess FREEWILL and to act as a FIRST CAUSE.

"Living things appear to possess freewill, and to that extent they appear free of the physical world with it's chains of causation.".

It is their freedom of action that makes living things stand out from the background of predictable causation.

Here we touch upon something remarkable. By definition, freewill operates without any sufficient preceding cause. Therefore freewill seems to transcend the natural environment. Freewill is a minor miracle and stands out in sharp contrast to the predictable events in it's environment. 

This is a premature conclusion to be sure. We will take a more detailed look at the Law of Causation later on. First we must gather all the definitions of life compiled by the scientists of many fields before we jump to conclusions. Such is the content of the following pages.

.....work in progress