Life as "Improbable Distribution of Molecules"

At the end of the last century Boltzman made an elegant redefinition of entropy as a measure of the probability of a molecular distribution. It may seem at first obscure, but it leads directly to what we seek. It implies that the probably life or one of its products, and if we find such a distribution to be global in extent then perhaps we are seeing something of Gaia, the largest living creature on Earth.

But what, you may ask, is an improbable distribution of molecules? There are many possible answers, such as the rather unhelpful ones: an ordered distribution of improbable molecules (like you, the reader), or an improbable distribution of common molecules (as, for example, the air). A more general answer, and one useful in our quest, is a distribution which is sufficiently different from the background state to be recognizable as an entity. Another general definition of an improbable molecular distribution is one which would require the expenditure of energy for its assembly from the background of molecules at equilibrium. (Just as our sand-castle is recognizably different from its uniform background, and the extent to which it is different or improbable is a measure of the entropy reduction or purposeful life-activity that it represents.)

We now begin to see that the recognition of Gaia depends upon our finding on a global scale improbabilities in the distribution of molecules so unusual as to be different and distinguishable, beyond reasonable doubt, from both the steady state and the conceptual equilibrium state.

Our search for life means looking for distributions of molecules that are unlikely, be they atmospheric proportions or solid constructions.