Why does positive mean descriptive

Question

I'm learning economics for the first time and they use the terms positive and normative economics to mean, respectively, the description of facts and the policy suggestions. This is the first time I've seen the word "positive" mean factual or descriptive. To me it means greater than zero or good or used to express certainty ("I'm positive that's correct!"). Based on some googling it seems like this positive/normative dichotomy stems from the philosophy world.

I'd like to understand the etymology of this meaning because it's so different than what I'm used to. Does it have something to do with "positing" a solution. (That doesn't really make sense to me either since I would say that when you posit something you're suggesting a possibility.)

Answer 1

According to the Online Etymology Dictionary (reformatted below), the senses that are more common nowadays actually came later:

positive [adjective]:

• early 14c, originally a legal term meaning "formally laid down, decreed or legislated by authority" (opposed to natural), from Old French positif (13c) and directly from Latin positivus "settled by agreement, positive" (opposed to naturalis "natural"), from positus, past participle of ponere "put, place"

• The sense of "absolute" is from mid-15c.

• Meaning in philosophy of "dealing only with facts" is from 1590s.

• Sense broadened to "expressed without qualification" (1590s),

• then, of persons, "confident in opinion" (1660s).

• The meaning "possessing definite characters of its own" is by 1610s.

• The mathematical use for "greater than zero" is by 1704.

• [† 1890s]

• Psychological sense of "concentrating on what is constructive and good" is recorded from 1916.

So the philosophy usage 'dealing with facts rather than opinions' is claimed to precede the 'confident of one's "facts" ' sense and the 'greater than zero' sense which are the default senses today.

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† For completeness, in response to Xanne's suggestion, here is the Wikipedia description of the coining of the terms positive economics and normative economics [repunctuated]:

Since its inception as a discipline, economics has been criticized for insufficiently separating prescriptive from descriptive statements ... and also for excessively separating prescriptive from descriptive statements.

The field's current emphasis on positive economics originated with the positivist movement of Auguste Comte [see Wikipedia] and with John Stuart Mill's introduction of Hume's fact-value distinction to define the science and art of economics in 'A System of Logic' which was introduced into the field by John Stuart Mill and was further developed by John Neville Keynes in the 1890s. John Neville Keynes's 'The Scope and Method of Political Economy' defined positive economics as the science of "what is" as compared to normative economics, the study of "what ought to be". Keynes was not the first person to make the distinction between positive and normative economics, but his definitions have become the standard in economics teaching.

Xanne is doubtless correct in believing that the distinction was made to give the study of economics credibility, the respectability associated with a science, with empirical analysis and interpretation of actual economic situations, using tested mathematical models ... rather than the disrepute associated with risky speculation.