In science, metaphysics is the study of the minor and major abstractions of the human mind—of which the major branches, according to American physical chemist Gilbert Lewis, are: space, time, matter, life (see: defunct theory of life), love, duty, and patriotism, and of which classical examples include: phlogiston and ether: [1]
“I should have liked to use the word ‘metaphysics’ in the title of this book, but there are certain words which have accumulated such evil implications that they must be abandoned, or withdrawn for a period of purification. Two such words, ‘phlogiston’ and ‘ether’, we shall have occasion to discuss in later lectures. However, in its best sense metaphysics might well be defined as the study of the major abstractions of the human mind, such as space, time, matter, life, love, duty, patriotism—we need not enumerate further. A more or less complete list of our major and minor abstractions is furnished by any unabridged dictionary.”