Thinking About Information Value

It is easy to forget that entropy, along with most of the other thermodynamic properties of a system, is fundamentally a feature of the external boundary of that system plus the internal boundaries that distinguish the system components, determining their possible interrelationships and hence, the space of systemic microstates. But how are these boundaries drawn in life, as opposed to Thermodynamics 101? To say that they are ‘given in experience’ is no answer this side of Nelson Goodman, Saul Kripke, and the later Ludwig Wittgenstein. Here in fact we may take a hint from Goodman and his theory of ‘projectability’, which conditions the induction of a relationship in any current case upon the past use history of the predicate that is attributed including successes and failures. This points to natural selection, and the consideration that, in nature, the detection of the internal and external boundaries of a thermodynamic system is, quite literally, the work of a physical device that selection has configured to detect the categories by which the boundaries are distinguished (and unless we want to be supernaturalists, there is no fundamental distinction between detection and work: i.e., to detect a signal is to be triggered by the signal to carry out some task, which we may as well consider a computation, expending some quantum of energy as it is executed).

Therefore we cannot speak of the absolute entropy, or the absolute information value of any state of a physical system independent of an organism or device which assesses that system’s internal and external boundaries. The entropy is a function of the system boundary and the space of possible microstates, and these in turn are conditional on what the detector is configured to detect. Use a different detector, and you draw the boundaries differently get a different entropy. Or take any arbitrary ‘slice’ of the plenum that you please; it is always possible to imagine some evolutionary history that would produce a detector able to extract useful work from, and therefore to detect, just that configuration within its context of internal and external boundaries.