3 ideas
The encyclopedia arranges its chapters by how essential each product is to human survival. It opens with grain cultivation, moves through clothing, salt, and tools, and ends with pearls and jade, following the stated principle of valuing the five grains over gold and jade. The order of a reference work is itself an argument about what matters, and putting luxuries last inverts the usual hierarchy where rare, beautiful things get the most attention.
Nature supplies raw potential, such as ores in rock, fiber in cocoons, and salt in brine, but that potential is only realized when human technique extracts and transforms it. Production is a partnership in which natural process and human craft are each insufficient alone. Understanding any product therefore means knowing both its natural source and the specific human steps that 'open' it.
Song records that sericulturists paired males of one silkworm variety with females of another, for example crossing yellow-cocoon and white-cocoon strains, to produce hybrid offspring with better traits. The case shows practitioners deliberately using heredity through controlled mating long before any formal theory of inheritance existed. It illustrates how systematic craft experimentation can arrive at biological principles empirically.