More Than Two Kinds of Waves

The Universe is Made Up of Two Kinds of Waves > Contrast > The Many Waves and How They Interact in the Ocean
Jeans puts waves into two categories of matter and radiation, but Carson's waves of the ocean fall into neither category, but are waves of mass and velocity.

 A Universe of Waves

Richard Feynman Describes the Waves Running Through Our Environment > Contrast > The Universe is Made Up of Two Kinds of Waves
Feynman and Sir Jeans on the waves permeating our Universe. Feynman focused on the invisible that fall into a myriad of categories, Jeans focuses on two categories.

 The Difficulty of Defining Species

Species Divisions are Complicated > Similarity > Are There Bacteria Species?
Dawkins describes the difficulty of defining any species, with missing links making it possible at all; while Frederick William Andrewes describes the difficulty of classifying bacteria, where rapid evolution and gene swapping magnify the issues Dawkins describes.