"3. Dates, as in Smith₁¹⁹²⁰, Smith₁¹⁹⁴⁰, Smith₁¹⁹⁵⁰ ... Smith₁^t. The use of dates places us in a physico-mathematical, four-dimensional (at least) space-time world of motion and change, of growth, decay, transformation, etc., yet the representations of the processes can be arrested at any given point by linguistic means for purposes of analysis, clarity, communication, etc. This gives us techniques to handle dynamic actualities by static means.
Thus, it probably would make a good deal of difference whether a given automobile is a 1930 or a 1950 model, if we are interested in buying one. We are not as a rule similarly conscious of "dating" our theories, creeds, etc., however, although it is "well known" to what extent dates affect science, theories, books, different customs and cultures, people and all life included.
As another example, if we read the Communist Manifesto by Karl Marx and Friedrich Engels (31) we find the word "modern" on many pages. It is easy to evaluate the "modern" as "1950," which apparently many readers do. My suggestion is that when we find that word we put on the margin by hand the date "1848." With that dating, many arguments become antiquated, and so obsolete, because we are living in the world of 1950, which is entirely different."
— Alfred Korzybski, The Role of Language in the Perceptual Processes.

In general semantics, the dates are a kind of index. Their interest and use are similar to that of indexes. This tool enables us to remember that things, people, theories, etc., change over 'time'.

Examples:

We can say for example: "Scientists₁₈₉₀ believed in the existence of ether", "Smith₁₉₇₀ was communist", "Capitalism₁₉₀₀ is not capitalism₁₉₉₇", etc.