[Note:J.C. Loudon's "Gardening Science - the Vegetable Kingdom" was published as Part 2, Book 1 of JC Loudon's " Encyclopedia of Gardening". This edition was (1) edited by JCL in 1834 (2) re-published by Jane Web Loudon in 1850 (3) scanned, edited and re-titled by Tom Turner (TT) in 2005 (4) published in copyright, with Loudon's paragraph numbers retained so that scholars can find page numbers from the printed edition].
980. Knowledge, in the infancy of every art, is necessarily confined to particulars, but after long observation and experience, the mind begins to generalise facts ; and this is the first step towards the foundation of theory, or science ; which is nothing more than the substitution of rational principles of action, for habits founded on custom or prejudice. A number of generalised facts being accumulated, the next process of the mind is to classify or systematise them; this is the highest effort in the progress of knowledge; and that art will be the most perfectly understood as a science, in which the greatest number of facts, or, in other words, the most extensive range of experience and observation, is generalised and arranged in a connected system.