Mathematical Models and the Newtonian Worldview
Further Reading: Differential Equations
- Recommended Textbooks: Blanchard, Devaney, and Hall (2011) is highlighted for its dynamical systems perspective and balance of qualitative, numerical, and analytic methods.
- Mathematical Biology Resources: Key texts include Britton (2005), Edelstein-Keshet (2005), Ellner and Guckenheimer (2006), Garfinkel et al. (2017), Mangel (2006), and Vandermeer and Goldberg (2013).
The Newtonian Mechanistic Worldview
- Newton's Principia (1687): Isaac Newton established a unified account of gravity and three universal laws of motion, framing the universe as a machine governed by unchanging mathematical rules.
- Core Assumptions: The traditional view assumes that simple mathematical laws lead to simple, predictable behavior. Complexity was historically thought to arise only from many interacting objects or non-simple laws.
Laplacian Determinism
- Laplace's Demon (1814): Pierre-Simon de Laplace posited that a "vast intelligence" knowing the position and forces of all particles could perfectly predict the past and future.
- Scientific Requirements for Prediction:
1. Knowledge of the universal laws of nature.
2. Accurate measurements of the current state.
3. Sufficient computing power.
- Challenges from Dynamical Systems: Modern study of chaos shows that even simple deterministic systems can be unpredictable due to sensitive dependence on initial conditions.
Styles and Levels of Mathematical Models
- Faithful vs. Caricature Models: Some models aim for exact quantitative prediction (like projectile motion), while others (caricatures) highlight essential features or qualitative traits (like an artist's sketch in a bird guide).
- First-Principles vs. Empirical Models:
* First-principles: Mechanistic models based on fundamental laws governing a system's constituents.
* Empirical: Descriptive models (e.g., linear regression) that capture trends in data without explaining the underlying mechanism.
- Abstraction Levels: Elements in models range from physical objects (point particles) to coarse-grained variables like temperature, population, and density.
- Agent-Based Models (ABMs): Instead of using population averages, ABMs simulate the movement and interaction of individual entities (agents) to see emergent behavior.
Pluralistic Modeling
- Contextual Effectiveness: The value of a model depends on its purpose. For example, a fetal pig and a mannequin are both valid models of a human body, but only for specific, non-interchangeable goals (physiology vs. clothing design).
- The Pluralistic View: No single model is "true." A full understanding of complex systems requires multiple models at different levels to illuminate various facets of the phenomenon.