SBVR — wrong proposition in 8.1.2 and modal formulation

Doc: dtc/06-03-02
Date: March 2006
Version: Interim Convenience Document
Chapter: 8.1.2 and 9.1.1, modal formulation
Pages: 101
Nature: Editorial
Severity: minor

Description:

In 8.1.2, 'obligation' is defined as follows:
"Definition: proposition that is required to be true, that is obligatory, that is not permitted to be false"

And 'permission', 'necessity' and 'possibility' are similar.

The problem is that an obligation is not a proposition that is required to be true. It is rather a proposition that requires another proposition be true.

Example:
"It is an obligation that every rental car has a scheduled service."
The proposition
'Every rental car has a scheduled service'
is what the obligation requires to be true. But that proposition itself is not an obligation. It is just a statement, like "all roads lead to Rome".

The 'obligation' is:
"It is an obligation that every rental car has a scheduled service."
or equivalently:
"Every rental car is required to have a scheduled service."
which is a different proposition.

The obligation itself is a proposition that (per the definition of 'proposition') can be true or false – that 'obligation' may or may not actually be a rule at UDriveIt.

The Note under the glossary entry for 'modal formulation' has this same error. It says:
"The meaning of a modal formulation is the proposition that the proposition meant by the embedded logical formulation is an instance of the modality claimed by the modal formulation."

I read this to say that the meaning of
"It is an obligation that every rental car has a scheduled service."
is the proposition:
"(The proposition) 'every rental car has a scheduled service' is
an (instance of) obligation."
This is incorrect. As above, the embedded proposition 'every rental car has a scheduled service' is not an obligation. The obligation is the meaning of the modal formulation itself.

That is, the meaning of a modal formulation is the proposition resulting from interpreting the proposition meant by the embedded logical formulation under the modality claimed by the modal formulation.

Recommendation:

In 8.1.2,

a. change the definition of 'necessity' to
"proposition that another proposition is necessarily true, always true"

b. In the definition of 'possibility', after "proposition that" insert "another proposition"

c. In the definition of 'obligation', after "proposition that" insert "another proposition"

d. In the definition of 'permissiblity', after "proposition that" insert "another proposition"

In 9.1.1,

a. Replace the text of the Note under 'modal formulation' with:
"The meaning of a modal formulation is the proposition resulting from interpreting the proposition meant by the embedded logical formulation under the modality claimed by the modal formulation."

b. Under the entry for 'modal formulation claims modality', add a note:
Note: The meaning of 'modal formulation claims modality' is that the proposition meant by the modal formulation is an instance of the concept that corresponds to the modality.

DUPLICATE OF ISSUE 9721