THERMODYNAMICS, INFORMATION AND LIFE REVISITED - PART-I - TO BE OR ENTROPY

Our whimsical title reflects our dismay over the rampant confusion reg arding the use of key concepts from thermodynamics and information the ory in various disciplines, but especially in relation to theories of biological evolution. After a brief introduction to this challenging l iterature, we begin by drawing a critically important distinction betw een 'order' and the informed 'functional organization' that characteri zes living systems. We then outline what we believe is the appropriate paradigm for theorizing about the role of energy and information in b iological processes; in essence, our paradigm is cybernetic. This is f ollowed by a brief discussion of thermodynamics, with particular refer ence to its application to living systems. Two concepts that are well developed in the engineering literature but not commonly used elsewher e provide an approach that we believe is both more rigorous and more r eadily understood, namely the 'control volume' frame of reference and the concept of 'available energy'. Both of these concepts are defined in precise mathematical terms. We also critique some of the misuses of thermodynamic concepts. In Part II, we will discuss what we call the 'thermoeconomics' of living systems - that is, a cybernetic and econom ic approach to analyzing the role of available energy in biological ev olution - and we will relate this paradigm to a distinction that we dr aw between various statistical and/or structural definitions of inform ation and what we call 'control information'. We will critique informa tion theory and we will define control information in cybernetic terms not as a 'thing' but as an attribute of the relationships between thi ngs - namely, the capacity (know-how) to control the acquisition, disp osition and utilization of matter/energy in purposive (teleonomic) pro cesses. We will also suggest how control information can be measured e mpirically, and we will propose a methodology for linking thermodynami cs and information theory that contrasts sharply with existing approac hes to this problem. Finally, we will argue that in living systems the rmodynamic processes may be subject to certain law-like 'bioeconomic' principles. We will also elucidate some implications. (C) 1998 John Wi ley & Sons, Ltd.