Mécanismes

Mécanismes refers to processes or devices that produce a particular effect, and the term is used across disciplines to describe how actions translate into outcomes. In engineering, a mechanism is a system of rigid bodies connected by joints through which motion and forces are transmitted and transformed. In biology, social sciences, and technology, mechanisms explain how observed results arise from underlying structures or rules.

A mechanism typically consists of a kinematic chain, joints (revolute, prismatic, etc.), and a fixed frame. The objective is to convert input motion or force into a desired output, often while controlling speed, direction, and torque. Common classes include levers, linkages, gear trains, cams, and screw mechanisms. Key concepts include degrees of freedom, constraints, efficiency, and backlash.

Biological mechanisms describe causal processes at the molecular, cellular, and organism levels. Examples include biochemical pathways, enzyme cascades, signal transduction networks, and homeostatic feedback loops (e.g., temperature regulation). Understanding biological mechanisms helps explain why perturbations lead to particular phenotypes or responses.

In social sciences and behavioral sciences, mechanisms describe the causal processes linking actions to outcomes, such as incentive structures, information flows, and normative pressures. Mechanism-based explanations emphasize the sequence of steps or interactions that translate an intervention into effect, rather than just correlations.

Mechanisms can be represented with diagrams, equations, or simulations, and are central to mechanism design, systems engineering, and mechanistic modeling. The term thus spans practical devices and abstract explanations, underscoring the interdisciplinary role of mechanisms in understanding, designing, and optimizing complex systems.