A longstanding philosophical premise perceives simplicity as a desirable attribute of scientific theories. One of several raised justifications for this notion is that simple theories are more likely to indicate the true makeup of natural systems. Qualitatively parsimonious hypotheses and theories keep to a minimum the number of different postulated entities within a system. Formulation of such ontologically simple working hypotheses proved to be useful in the experimental probing of narrowly defined bio systems. It is less certain, however, whether qualitatively (...) parsimonious theories are effective indicators of the true nature of complex biological systems. This paper assesses the success of ontologically simple theories in envisaging the makeup of three complex systems in bacteriology, immunology, and molecular biology. Evidence shows that parsimonious theories completely misconstrued the actual ontologically complex constitutions of the three examined systems. Since evolution and selective pressures typically produce ontologically intricate rather than simple bio systems, qualitatively parsimonious theories are mostly inapt indicators of the true nature of complex biological systems. (shrink)

In a short 1997 book entitled Simplicity as Evidence of Truth, the Oxford philosopher Richard Swinburne has put forward the following thesis summarily: ‘… for theories (of equal scope) rendering equally probable our observational data (which, for brevity I shall call equally good at “predicting”), fitting equally well with background knowledge, the simplest is most probably true’.

I give a detailed defence against Grunbaum’s 2004 attack on my Bayesian argument for the existence of God from various features of the universe (its conformity to simple laws, the laws being such as to lead to the evolution of humans, etc.). Theism postulates the simplest possible stopping point for explanation of the various features which I mention, and is such that it makes the accounts of those features more probable than they would be otherwise.