A Brief Ontology Of Time

“Clocks slay time… time is dead as long as it is being clicked off by little wheels; only when the clock stops does time come to life.”

William Faulkner

Preamble

The melting of digital fences between enterprises and business environments is putting a new light on the way time has to be taken into account.

Joseph_Koudelka_time
Time is what happens between events (Josef Koudelka)

The shift can be illustrated by the EU GDPR: by introducing legal constraints on the notifications of changes in personal data, regulators put systems’ internal events on the same standing as external ones and make all time-scales equal whatever their nature.

Ontological Limit of WC3 Time Recommendation

The W3C recommendation for OWL time description is built on the well accepted understanding of temporal entity, duration, and position:

Cake_time

While there isn’t much to argue with what is suggested, the puzzle comes from what is missing, namely the modalities of time: the recommendation makes use of calendars and time-stamps but ignores what is behind, i.e time ontological dimensions.

Out of the Box

As already expounded (Ontologies & Enterprise Architecture) ontologies are at their best when a distinction can be maintained between representation and semantics. That point can be illustrated here by adding an ontological dimension to the W3C description of time:

  1. Ontological modalities are introduced by identifying (#) temporal positions with regard to a time-frame.
  2. Time-frames are open-ended temporal entities identified (#) by events.
Cake_timeOnto
How to add ontological modalities to time

It must be noted that initial truth-preserving properties still apply across ontological modalities.

Conclusion: OWL Descriptions Should Not Be Confused With Ontologies

Languages are meant to combine two primary purposes: communication and symbolic representation, some (e.g natural, programming) being focused on the former, other (e.g formal, specific) on the latter.

The distinction is somewhat blurred with languages like OWL (Web Ontology Language) due to the versatility and plasticity of semantic networks.

Ontologies and profiles are meant to target domains, profiles and domains are modeled with languages, including OWL.

That apparent proficiency may induce some confusion between languages and ontologies, the former dealing with the encoding of time representations, the latter with time modalities.

Further Readings

External Links

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