Systems complexity is increasing, in particular, when systems become systems of systems (SoS). SoS are composed of constituent systems (CS), have unique goals for the CS and the SoS as a whole, and present new SoS-level properties called emergent properties. Emergent properties are unique because they only appear at the system level. Current research has only revealed some tools focusing on simple emergence for engineers aiming to design emergence at the SoS level. However, forming design tools for the creation or modification of strong emergence will enable engineers to create systematic changes in the SoS. This article proposes a connection between emergence and information streams with the latter being a model of the transfer of information between the different CS in the SoS. A methodology for designing SoS information streams is demonstrated, with encouraging results, using a multi-agent simulation of the propagation of the COVID-19 virus through citizens. By testing several information stream configurations, an SoS with a decrease of 47% in sick agents was found. These results show that by changing the information stream better SoS performance is attained, supporting designing in a complex world.

More realistic approaches are needed to understand the complexity of ecological systems. Emergent properties of real systems can be used as a basis for a new, neither reductionist nor holistic, approach. Three systems, termed here BUBBLEs, WAVEs and CRYSTALs, have been identified as exhibiting emergent properties. They are non-hierarchical assemblages of individual components, with amplification and connectedness being two main principles that govern their build-up, maintenance and mutual relationships. Examples from various fields of biological and ecological science are referred to, ranging from individual organisms to landscapes.

This article argues that Lockwood's piece on social and system integration was quite insightful at the time, but that it failed in correctly solving the issues it raised. More recent versions of the distinction, such as Giddens's and Archer's, are deemed not satisfactory either. Three steps are then taken in order to provide an alternative solution, which tackles the general problem of the relationship between structure and agency.The critical analysis of the notion of ‘emergent properties’, along with those of ‘structure’ and ‘mechanism’, is the groundwork for a discussion of collective causality that substantiates an alternative view which deÞnes social systems as collective subjectivities, including some methodological considerations. A broad notion of realism is upheld in the article.

The geological theory of the evolution of the material environment and the biological theory of the evolution of organisms by natural selection are usually treated separately. This paper presents a new evolutionary theory, in which the evolution of the organisms, and the evolution of their material environment, are seen to be so closely coupled as to form a single, indivisible, process. This combined evolutionary system can be taken to be a domain with emergent properties unexpected from a simple addition of its component parts, rather like the eighteenth-century scientific view of the Earth as a super-organism. In homage to James Hutton, who lectured before the Royal Society of Edinburgh about the Earth as a super-organism and on the physiology of the Earth, the new topic is called geophysiology.

The difference between the geophysiological view of the Earth, where the environment and the organisms are tightly coupled, and the co-evolutionary, or biogeochemical view, where the coupling is loose leaving organisms and their environment to evolve more or less separately, is discussed. The paper includes numerical models to illustrate how a close-coupled evolutionary system could have self regulation, homeostasis, as an automatic and emergent property. The models will be compared with the real world past and present and their predictions examined.