僕が参加しているあるMessengerのグループ（文筆家、編集プロ経営者、校正者、翻訳者）で構成されている）に、「every と all の違いについて」というお題が出された。
参加者のお一人（問題の提出者）から、次の引用が示された。「all も every もともに人や物、またはグループの成員すべてを一般的に話題にするとき用いることができる。両語の間に意味の違いはほとんどない。every は ‘without exception'（例外なく）を示唆することが多い。両者とも、異なる構造で用いられる。【オックスフォード実例 現代英語用法辞典 第3版、p.55】」
そこで、僕も「どうだったかな？」と思い、ChatGPTに軽く尋ね、その後興味がわいたのでこの問題を少し掘り下げてみることにした。
以下はその記録である。
（１）every と all の違いは何か
問１：How, or to what extent are 'every' and 'all' different? Please explain to me as clearly as possible, with sample sentences if possible.
回答１：The words "every" and "all" are often used to refer to the entirety of a group or number of things, but they differ in how they are applied.
"Every" is used when referring to individual elements of a group, one by one. It emphasizes each single member or part of the group. "Every" is typically followed by a singular noun.
Example: "Every student in the class must complete the assignment." This means each individual student (one by one) must complete the assignment.
"All" is used to refer to the whole group collectively, not emphasizing individual elements. "All" is typically followed by a plural noun or an uncountable noun.
Example: "All students in the class must complete the assignment." This means the entire group of students, as a whole, must complete the assignment.
In summary, "every" focuses on individuals within a group, while "all" focuses on the group as a whole.
まあ、常識的な答えです。そこで、この問題をもっと掘ってみることにした。
（２）もっと具体的に教えてほしい。
問２：Could you clarify the degree of difference more clearly?と聞いてみた。
回答２：The degree of difference lies in the focus and implication of these words when used in sentences.
Focus on Individuals vs. Focus on the Group:
"Every" puts the spotlight on individual members of a group. It's as if you are pointing to each member and noting them separately.
"All" considers the group as a single entity. It's like stepping back and looking at the entire group together.
Implication of Completeness:
When you use "every", it often suggests a more thorough or detailed consideration of each member. It implies no one is left out.
"All" implies completeness, but without the emphasis on individual members. It's more about the collective whole.
Contextual Usage:
"Every" is typically used when the individual actions or characteristics of each member are important.
"All" is used when you want to refer to the entire group and the individual specifics are less important.
For example:
Saying "Every piece of art in the gallery is unique" implies that you are focusing on the uniqueness of each individual piece.
Saying "All the art in the gallery is unique" implies the collection as a whole is unique, without focusing on each piece separately.
This difference in focus and implication is the key to understanding the subtle distinction between "every" and "all."
（３）最初に示された文章【オックスフォード実例 現代英語用法辞典 第3版】に「every は ‘without exception'（例外なく）を示唆する」とあった、そこでこの点を掘ってみることにした。
問３：Is the issue of exceptions related to the use of 'all' and 'every'?
回答３：The use of "all" and "every" does not inherently include exceptions. When you use "all" or "every," you are typically including the entire set of items or individuals you're referring to, without exception. However, in everyday language, people sometimes use these terms and still imply or acknowledge exceptions. This is more about the pragmatics of language — how people use words in different contexts — rather than the literal meaning of "all" and "every." For example, a teacher might say "Every student passed the test," even if one or two did not, particularly if the vast majority did and the teacher is emphasizing the general success of the class.
な～るほど。理屈ではeveryは例外を含まないけれども、現実の会話の場ではそうでないこともあるってことね。
（４）ここまでのChatGPTの説明はかなり説得力があるけれども、一応根拠を尋ねてみた。
問４：Could you provide me with a URL or link that supports your argument above?
回答４：I've found a source that explains the use of "all," "every," and "each" in English grammar. According to Grammar.cl:
"All" means the total number of people or things considered as a group.
"Every" refers to all members of a group considered individually.
"Each" also refers to all members of a group considered individually but with a sense of looking at them more one by one【20†source】.
Furthermore, "every" is generally closer in meaning to "all" than "each" is. However, it is noted that "every" cannot be used when referring to two things and is not common with small numbers. For instance, "every one of my parents" is incorrect, whereas "each of my parents" is correct【21†source】.
Additionally, "all" refers to the total number of people or things in a group, where they are considered as a group and not individually, and it is typically used when there are at least three things in the group【22†source】.
These explanations do not imply exceptions but rather clarify the contexts in which each term is typically used. If you wish to look at this topic more comprehensively, you can visit the full article here.
All, Every, Each - English Grammar
（５）上のYoutubeはallとeachの違いに関するわかりやすい説明で、わかりやすい例文が紹介されていた。
(1） I say goodbye to all of the students as they leave the room.
(2) I say goodbye to each student as they leave the room.
生徒が20人いたとすると、（１）では先生はgoodbyeと1度しか言わないが、（２）では20回言う、と。
そこで、この答えを元に、対象をeveryまで広げて次の質問をした。
問５：Assuming that there are 20 students in the class. How many times does the teachere say "goodbye " in each case?
(1) I say goodbye to all of the students as they leave the room.
(2) I say goodbye to each student as they leave the room.
(3) I say goodbye to every student as they leave the room.
回答５：I say goodbye to all of the students as they leave the room: In this case, the teacher says "goodbye" once to the entire group of students. Therefore, the teacher says "goodbye" 1 time.
I say goodbye to each student as they leave the room: Here, the teacher says "goodbye" individually to each of the 20 students. Therefore, the teacher says "goodbye" 20 times.
I say goodbye to every student as they leave the room: This is similar to case 2. Saying "goodbye" to every student individually also means the teacher says "goodbye" 20 times.
In summary, the teacher says "goodbye" 1 time in the first scenario and 20 times in both the second and third scenarios.
以上。
ChatGPTって単なる一問一答で終わるものではなく、問題を掘っていけるなあ、そんなことを思ったのでここに記録した次第です。
＊余談：今度このグループで飲みに行くんですわ。何しろ僕以外は「オタク」の集団なので、最初から最後まで国語とか文法とか翻訳の話題に終始しそうで（前回は「最初の一杯」が来る前にご自分のカバンから資料を取り出して「この問題は～」と始めたお兄さんがいましたっけね）私は今から戦々恐々としているのである。
