2.1.6 Some ambiguities in the daily use of "is" and "is not"

In the four daily judgments (propositions) (a-type, i-type, e-type, o-type), the words "is" and "is not" are used for affirmation and negation.If you think deeply about these two sets of words, you will find that these two sets of words are widely used in daily life and can easily cause ambiguity.

The "is" is a daily use vocabulary if it is indicated by a mathematical symbol that the "=" symbol should be used.If the word "is" is used in accordance with such a rule, the word "is" is basically useless except for mathematical expressions and some abstract forms of logical expressions. (This is because in the material or real world, no two things are exactly the same.) In the case of many daily constants, the concept of "is" should strictly be "belonging".

E.g.

NASDAQ stocks are publicly traded stocks in the United States.

This sentence should be strictly stated as:

NASDAQ stocks belong publicly traded stocks in the United States.

When using the term "is" to connect two different concepts, readers should always remember that no two things are exactly the same.

There is another situation, that is, even if the same concept cannot be linked with "=" at different points in history over time.

Please review the map of the Dow Jones Industrial Index mentioned in the series "1.1.5.2 Changes in sample stocks and stock index distortion":

As for the word "is not", if you go deeper, the meaning behind it in daily use is mostly a concept of "not belonging". The word "is not" is not as ambiguous as "is", because when the concept of "not belonging" is established, "is not" is also established. It’s just that everyone doesn’t delve into their true intentions in everyday language.

E.g:

Some blue chips are not the DJIA index stocks.

The meaning can also be "some blue chips do not belong to the DJIA index stocks."

More articles, please see "English version index"