DTV — Date-Time Issue: now is not synonymous with current

There are some terms that map to the same underlying concepts, but they are not synonymous because one cannot be substituted for the other. Often this is a matter of how they fit into context as being relative or not. In particular:
a. “now” is not synonymous with “is current”
b. “today” is not synonymous with “current day”
c. “tomorrow” is not synonymous with “upcoming day”
d. “yesterday” is not synonymous with “previous day”
Proposed Resolution:
(The submission team adopted these changes after the final submission. They are recorded here so that the FTF team can reconsider them.)

Make these changes in clause 9.2:
• Insert the article "the" in front of the Definition of "time interval is current" so that the Definition reads: "the time interval includes a time interval1 that is past and includes a time interval2 that is not past"
• Add a new glossary entry:
time interval is now
Definition: the time interval overlaps the time interval of utterance
Note: "Time interval of utterance" means the time interval when a proposition is given, as opposed to when the proposition is evaluated.

The following actions are pending, from the minutes of the submission team conference call on September 9, 2011:
• Distinguish “today” (and similar concepts) from “current day”.
• Make sure all fact type definitions use the appropriate style
• Find and fix relative times that are styled as individual concepts but aren't.
• Clarify note under “day” to make it clear (if it isn't already) that we ignore leap seconds.

The DTV FTF-2 team chose to focus clause 15 "Indexical Concepts" on 'current time' and delete all support for 'now'. Reasons for this include:

• As best practice and to avoid ambiguity, rules that need to refer to the time when a rule is stated (put into effect) should reference that time by a time coordinate or as an occurrence.
• To avoid an 'explosion' in the number of indexical concepts in this clause.

To implement this decision, clause 15 "Indexical Concepts" is reworked to provide only indexical concepts that are relative to 'current time'.

Similar changes are made to the characteristic 'state of affairs is now', and related characteristics, in clause 16.7.

For ease of use, the FTF-2 team decided to adopt a consistent naming pattern for the indexical time concepts. The naming pattern is described in the new clause 15.2