SESSION 1A: Inauguration & Presidential Address

Chairperson

The uses of chance

Chance, depending on context, can mean different things to different people. A chance event may either be a consequence of intrinsic fluctuations or may be due to incomplete or imprecise knowledge. The notion of contingency is closely tied into that of chance, and thus uncovering the underpinnings – whether this is due to underlying stochastic phenomena or underlying chaotic dynamics – is of interest. Using examples from dynamical systems theory, the role of chance when there are several coexisting dynamical attractors, with attractor basins that are intermingled in a complex manner will be discussed. Small uncertainties in determining the initial state can lead to very large uncertainties in the outcomes. On the other hand, intrinsic noise plays a major role in small systems where the dynamics is stochastic. Both phenomena occur in biological systems and are exploited, at a systems level, in different ways. On the one hand, chance provides the possibility of complex dynamical states such as chimeras. On the other, chance allows for stochastic switching in the realm of dynamics both within a cell and within populations. Chance is crucial in a diverse range of situations. To paraphrase Monod (1971), nature relies on chance and not on destiny. And as noted by C R Rao (1989), chance may be the antithesis of all law. But the way out is to discover the laws of chance. extra line. one.