Systems involving many interacting variables are at the heart of the natural and social sciences. Causal language is pervasive in the analysis of such systems, especially when insight into their behavior is translated into policy decisions. This is exemplified by economics, but to an increasing...

The Cambrian explosion involved an extraordinary evolutionary event with sudden appearance of most metazoan (animal) body plans. Different aspects are involved in this event, from the molecular organization of gene networks to ecological factors. In this review, this event is explored from...

Profit maximization is difficult. Sophisticated and experienced managers often disagree about which action is most likely to maximize profits for a given firm. Economic models of profit maximization, on the other hand, are---in general---easy. Well-trained economists can readily discern the...

With state-level societies in mind, Bruce Trigger (1990) characterized monuments as a form of conspicuous consumption flaunting the ability of the elite to defy the principles of least-effort that are so important in structuring other aspects of social and economic organization. The prehistoric...

Conditions for invasion by a new allele that controls the recombination pattern among an arbitrary number of genes under viability selection are studied. The recombination pattern may include interference. The new allele increases if its appropriately averaged marginal fitness is greater than...

For many organisms, and especially for the model organisms of molecular and cell biology, the primary locus of study is the laboratory, and not their natural habitat. Thus, a huge body of knowledge accumulated through a century of laboratory studies contrasts with the limited amount of...

Recent experiments involving competition of clonal populations of RNA viruses have shown that competition among virus strains of approximately equal relative fitness can result in the eventual competitive exclusion of one of the species. As competition proceeds in time, both the winers and the...

A common first step in time series signal analysis involves digitally filtering the data to remove linear correlations. The residual data is spectrally white (it is ``bleached''), but in principle retains the nonlinear structure of the original time series. It is well known that simple linear...

A framework for studying the evolution of cooperative behaviour, using evolution of finite state strategies, is presented. The interaction between agents is modelled by a repeated game with random observable payoffs. The agents are thus faced with a more complex (and general) situation, compared...

We introduce a new model of evolution on a fitness landscape processing a tunable degree of neutrality. The model allows us to study the general properties of molecular species undergoing neutral evolution. We find that a number of phenomena seen in RNA sequence-structure maps are present also...