On The Philosophy of Nature: A Guide to the New Essentialism (2002). What kind of metaphysics underlies chemistry and physics? Ellis argues that items such as chemical elements and physical particles have essences, and that these essential properties determine their behavior, which is characterized by scientific laws. Thus, these laws are necessary; they apply in all possible worlds. Get more at partiallyexaminedlife.com. Visit partiallyexaminedlife.com/support to get ad-free episodes and tons of bonus discussion. Sponsor: Get a $1/month e-commerce trial at shopify.com/pel. Learn about our new book at partiallyexaminedlife.com/book.