Book contents
- Frontmatter
- Contents
- Preface
- Outline of the book
- Part I Reconciling Natural and Mental Philosophy
- Part II Reconstructing Rational Mechanics
- 4 What is mechanics?
- 5 Kinematics
- 6 Dynamics
- 7 The character of mechanical law
- Part III Mechanical Minds
- Part IV The Metaphysics of Mechanics
- Part V Conclusion of the Matter
- System of Notation
- Bibliography
- Index
7 - The character of mechanical law
from Part II - Reconstructing Rational Mechanics
Published online by Cambridge University Press: 21 September 2009
- Frontmatter
- Contents
- Preface
- Outline of the book
- Part I Reconciling Natural and Mental Philosophy
- Part II Reconstructing Rational Mechanics
- 4 What is mechanics?
- 5 Kinematics
- 6 Dynamics
- 7 The character of mechanical law
- Part III Mechanical Minds
- Part IV The Metaphysics of Mechanics
- Part V Conclusion of the Matter
- System of Notation
- Bibliography
- Index
Summary
The axioms on forces given in the previous chapter characterize the nature of inertial forces and the structure of systems of forces in isolation, but otherwise say nothing about how forces arise in the evolution of mechanical systems. Although the special laws of forces depend on the specific class of material involved, Noll states three additional general axioms concerning dynamogenesis that bear on the general character of mechanical forces.
The first of Noll's general axioms on dynamogenesis states the principle of determinism, that the history of body and contact forces (or equivalently, the stress) at preceding instants determines a unique value for these forces at a given instant. The second axiom states the principle of locality, that the forces at a point depend only on the configuration of bodies within arbitrarily small neighborhoods of the point. The third axiom states the principle of frame indifference, that forces depend only on the intrinsic properties of motions and deformation, not on properties that vary with the reference frame.
Although we follow the pattern set by Noll regarding frame indifference, the broader mechanics requires some adjustment in the conceptions of both determinism and locality. The discrete materials of psychology and economics provide different and somewhat weaker motivations for determinism and locality of dynamogenesis, even if one winds up making traditional determinism and locality assumptions in specific systems.
- Type
- Chapter
- Information
- Extending Mechanics to MindsThe Mechanical Foundations of Psychology and Economics, pp. 173 - 222Publisher: Cambridge University PressPrint publication year: 2006