selection pressure summarises many reproductive outcomes just as gas pressure summarises many molecular motions

Categories: Comparisons

An example of an analogy between different areas of science,

"There is a causal story behind each and every mutation, each and every chiasma, each and every choice of a mating partner, each and every union of gametes, each and every catastrophe that did not happen. But this story is untellable because of incomplete information, chaotic dynamics, and computational complexity. And if it could be told, the story would be incomprehensible. One must simplify to tell a tale, giving greater salience to some items and leaving loose ends.

A pedant could argue that pressure is not an efficient cause and should be expunged from physical explanations–only individual molecular impacts are truly causal–but his argument would be dismissed as obfuscation. For questions at the appropriate scale, pressure provides a perfectly adequate explanation, indeed one that is superior to the unattainable account that describes each and every molecular collision. Darwinian final causes are similarly grounded in efficient causes and are perfectly adequate, indeed indispensable, for certain kinds of biological explanation. A 'selection pressure' summarises many reproductive outcomes just as the pressure of a gas summarises many molecular motions. Darwinism, like thermodynamics, is a statistical theory that does not keep track of every detail…"

Haig, David (2014). Fighting the good cause: meaning, purpose, difference, and choice. Biology & Philosophy, 29(5), 675-697. https://doi.org/10.1007/s10539-014-9432-4

Read about analogy in science

Read examples of scientific analogies

Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.

Author: Keith

Former school and college science teacher, teacher educator, research supervisor, and research methods lecturer. Emeritus Professor of Science Education at the University of Cambridge.