In this paper we provide some theoretical guidelines for the characterization of the specificity of biological systems in terms of organization and constraints. In the first place we advocate the view according to which a sound account of biological organization requires an appeal to emergent causation, and we propose a theoreti-cal justification of emergence against existing criticisms by consid-ering it as a causal power stemming from the relational properties of material configurations. Then, by interpreting constraints as a spe-cific form of this emergent causal power, we propose a distinction between the roles played by constraints in physical and biological systems. As a result we provide a possible definition of biological organization as a closed network of co-dependent and internally produced constraints.

Biological regulation is what allows an organism to handle the effects of a perturbation, modulating its own constitutive dynamics in response to particular changes in internal and external conditions. With the central focus of analysis on the case of minimal living systems, we argue that regulation consists in a specific form of second-order control, exerted over the core (constitutive) regime of production and maintenance of the components that actually put together the organism. The main argument is that regulation requires a distinctive architecture of functional relationships, and specifically the action of a dedicated subsystem whose activity is dynamically decoupled from that of the constitutive regime. We distinguish between two major ways in which control mechanisms contribute to the maintenance of a biological organisation in response to internal and external perturbations: dynamic stability and regulation. Based on this distinction an explicit definition and a set of organisational requirements for regulation are provided, and thoroughly illustrated through the examples of bacterial chemotaxis and the lac-operon. The analysis enables us to mark out the differences between regulation and closely related concepts such as feedback, robustness and homeostasis.

We propose a conceptual and formal characterisation of biological organisation as a closure of constraints. We first establish a distinction between two causal regimes at work in biological systems: processes, which refer to the whole set of changes occurring in non-equilibrium open thermodynamic conditions, and constraints, those entities which, while acting upon the processes, exhibit some form of conservation (symmetry) at the relevant time scales. We then argue that, in biological systems, constraints realise closure, i.e. mutual dependence such that they both depend on and contribute to maintaining each other. With this characterisation in hand, we discuss how organisational closure can provide an operational tool for marking the boundaries between interacting biological systems. We conclude by focusing on the original conception of the relationship between stability and variation which emerges from this framework. – Highlights:Biological systems realise both organisational closure and thermodynamic openness, Organisational closure is a closure of constraints, Constraints exhibit conservation (symmetry) at the relevant time scales, Closure draws the boundaries between interacting biological systems, Closure is a principle of biological stabilisation.

Key words: Biological organisation, Closure, Constraints, Symmetries, Time scales

Open peer commentary on the article “Sensorimotor Direct Realism: How We Enact Our World” by Michael Beaton. Upshot: The target article convincingly argues in favor of the idea that the sensorimotor account of perception provides a positive scientific context for direct realism. In some cases, however, perception and experience do not seem to fit easily with sensorimotor direct realism. This raises a question of scope that requires further elaboration.

This chapter offers an overview of the theoretical and philosophical tradition that, during the last two centuries, has emphasised the central role of circularities in biological phenomena. In this tradition, organisms realise a circular causal regime insofar as their existence depends on the effects of their own activity: they determine themselves. In turn, self-determination is the grounding of several biological properties and dimensions, as individuation, teleology, normativity and functionality. We show how this general idea has been theorised sometimes through concepts, sometimes through models, and sometimes through both. We analyse the main differences between the various contributions, by emphasising their strengths and weaknesses. Lastly, we conclude by mentioning some contemporary developments, as well ass some future research directions.

Key words: circularity, robert rosen, cybernetics, constraints, autopoiesis, biological organization

This paper argues that biological organisation can be legitimately conceived of as an intrinsically teleological causal regime. The core of the argument consists in establishing a connection between organisation and teleology through the concept of self-determination: biological organisation determines itself in the sense that the effects of its activity contribute to determine its own conditions of existence. We suggest that not any kind of circular regime realises self-determination, which should be specifically understood as self-constraint: in biological systems, in particular, self-constraint takes the form of closure, i.e. a network of mutually dependent constitutive constraints. We then explore the occurrence of intrinsic teleology in the biological domain and beyond. On the one hand, the organisational account might possibly concede that supra-organismal biological systems (as symbioses or ecosystems) could realise closure, and hence be teleological. On the other hand, the realisation of closure beyond the biological realm appears to be highly unlikely. In turn, the occurrence of simpler forms of self-determination remains a controversial issue, in particular with respect to the case of self-organising dissipative systems.

Key words: Teleology, organisation, self-determination, closure, circularity.

The central aim of this paper consists in arguing that biological organisms realize a specific kind of causal regime that we call “organisational closure”; i.e., a distinct level of causation, operating in addition to physical laws, generated by the action of material structures acting as constraints. We argue that organisational closure constitutes a fundamental property of biological systems since even its minimal instances are likely to possess at least some of the typical features of biological organisation as exhibited by more complex organisms. Yet, while being a necessary condition for biological organization, organisational closure underdetermines, as such, the whole set of requirements that a system has to satisfy in order to be taken as a paradigmatic example of organism. As we suggest, additional properties, as modular templates and control mechanisms via dynamical decoupling between constraints, are required to get the complexity typical of full-fledged biological organisms.

Ecological and sensorimotor theories of perception build on the notion of action-dependent invariants as the basic structures underlying perceptual capacities. In this paper we contrast the assumptions these theories make on the nature of perceptual information modulated by action. By focusing on the question, how movement specifies perceptual information, we show that ecological and sensorimotor theories endorse substantially different views about the role of action in perception. In particular we argue that ecological invariants are characterized with reference to transformations produced in the sensory array by movement: such invariants are transformation-specific but do not imply motor-specificity. In contrast, sensorimotor theories assume that perceptual invariants are intrinsically tied to specific movements. We show that this difference leads to different empirical predictions and we submit that the distinction between motor equivalence and motor-specificity needs further clarification in order to provide a more constrained account of action/perception relations.

Key words: Action, perception, self-motion, invariants, sensorimotor theories, ecological psychology, enaction

In this paper, we advocate the idea that an adequate explanation of biological systems requires appealing to organisational closure as an emergent causal regime. We first develop a theoretical justification of emergence in terms of relatedness, by arguing that configurations, because of the relatedness among their constituents, possess ontologically irreducible properties, providing them with distinctive causal powers. We then focus on those emergent causal powers exerted as constraints, and we claim that biological systems crucially differ from other natural systems in that they realise a closure of constraints, i.e. a higher-level emergent regime of causation such that the constituents, each of them acting as a constraint, realise a mutual dependence among them, and are collectively able to self-maintain. Lastly, we claim that closure can be justifiably taken as an emergent regime of causation, without admitting that it inherently involves whole-parts causation, which would require committing to stronger ontological and epistemological assumptions.

Key words: Emergent property, causal power, downward causation, biological domain.