Laws of Nature

Pragmatic Laws, Sandra D. Mitchell

  • the most important distinction:

“The function of scientific generalizations is to provide expectations of the occurrence of events and patterns of properties. (…) To know when to rely on a generalization to know when it will apply, and this can be decided only under what specific conditions it has applied before.” pg.477.

The patterns and conditions are two distinct words here. For example, if you’re working with the charged particles, you should be aware of their response to the electrical and magnetic fields, before thinking the gravitational force, which is Cartwright’s obsession. Fields provide patterns but under which conditions? How strong is the magnetic field, for example? Those are the questions you should ask if you want to generalize a rule.

  • a clarification question/criticism:

“The conditions upon which physical laws are contingent may be more stable through space and time than the contingent relations described in biological laws.” pg.478.

I could not see the primary difference between the physical and biological laws. If they have different traits, then we should question the properties and definition of a law at the beginning. But, this might be the normative approach.

Do the Laws of Physics State the Facts? Nancy Cartwright

  • the most important distinction:

“I have argued, a trade‐off between factual content and explanatory power. We explain certain complex phenomena as the result of the interplay of simple, causal laws.” pg.15.

I think she is trying to show simplifications and generalizations would result in lack of facticity. It is worth to discuss.

  • a clarification question/criticism:

“But this law of causal action is highly specific to the situation and will not work for combining arbitrary influences studied by transport theory.” pg. 9.

Fick’s Law is a specific case of the transport equation, if viscosity, body force and bulk velocity are comparably less significant. She is taking a specific case and trying to generalize a rule but the process should be the opposite. The general law is the conservation of momentum and it is represented by the transport equation. Fick’s law is a sub-case of the conservation law. Also, at pg 6, Coulomb’s Law is stated wrong! I just wanted to congratulate the editors of this article (if any)!

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