ceteris paribus(他の条件が同じならば)

友人と話をしていて、先ほど大恥をかいたので戒めの為にメモ。

英語の文章や論文でよく見るラテン語由来の単語として、こんなものがある・・・という話題で話していた。アド・ホックとか、etcとか。

まあ、それはいいのだけれど、ふと「他の条件が同じならば」という意味でよく見かけた単語を言おうとして、何故か出てこない。

最近、経済学の論文なんて読んだこと無いので、使ってないとすぐに忘れるなあ～と思っていたら、あろうことか「パリス・バーバラ？とかいう単語って無かったっけ？」と口走ってしまった私。

ググレども駄目、辞書引いても全然出てこないし、友人からは「パリス・ヒルトン？」などと冷やかされる始末。悔しくて延々と探し続けていてようやくこの単語に至る。

ceteris paribus

全然、違うじゃん。読み方も。なんか全然別な単語とアホな私は混同したらしい。「パリ」と「バ」しか合ってないし・・・あ～あ。

ちなみにこの単語を見つけたのは２ちゃんの板にて。みんなよく知ってますね。尊敬しますよ～。

つ～か、あまりにも勉強不足だな、私。もうちょっと勉強しようっと。その前に仕事の勉強もやらなきゃなのだけど・・・。

単語のもっとも詳しい説明はwikipediaより。

【以下、wikiより転載】
Cēterīs paribus is a Latin phrase, literally translated as "with other things [being] the same," and usually rendered in English as "all other things being equal." A prediction, or a statement about causal or logical connections between two states of affairs, is qualified by ceteris paribus in order to acknowledge, and to rule out, the possibility of other factors which could override the relationship between the antecedent and the consequent.

A ceteris paribus assumption is often fundamental to the predictive purpose of scientific inquiry. In order to formulate scientific laws, it is usually necessary to rule out factors which interfere with examining a specific causal relationship. Experimentally, the ceteris paribus assumption is realized when a scientist controls for all of the independent variables other than the one under study, so that the effect of a single independent variable on the dependent variable can be isolated. By holding all the other relevant factors constant, a scientist is able to focus on the unique effects of a given factor in a complex causal situation.

Such assumptions are also relevant to the descriptive purpose of modeling a theory. In such circumstances, analysts such as physicists, economists, and behavioral psychologists apply simplifying assumptions in order to devise or explain an analytical framework that does not necessarily prove cause and effect but is still useful for describing fundamental concepts within a realm of inquiry.



Ceteris paribus in economics

One of the disciplines in which ceteris paribus clauses are most widely used is economics, in which they are employed to simplify the formulation and description of economic outcomes. For example, it can be predicted that if the price of beef decreases — ceteris paribus — the quantity of beef demanded by buyers will increase. In this example, the clause is used to operationally describe the relationship between both the price and the quantity demanded of an ordinary good.

This operational description intentionally ignores both known and unknown factors that may also influence the relationship between price and quantity demanded. Such factors include: the relative change in price of substitute goods, (e.g., the price of beef vs pork or lamb); the level of risk aversion among buyers (e.g., fear of mad cow disease); or the level of overall demand for a good regardless of its current price level (e.g., a societal shift toward vegetarianism).

The clause is often loosely translated as "holding all else constant."

そう言えば、facsimile や vice versa もラテン語由来なんだね。意外に身近なところに転がってますね。