Databases Reference
In-Depth Information
represents. They understand, of course, that we may sometimes
be wrong; but they assume that our intention is to be truthful,
and that we take reasonable care to be accurate. Without those
assumptions, the creation and maintenance of data would be a
pointless activity.
So underlying the activity of creating, maintaining and con-
suming data lies the matter of what we claim or assert to be true.
For purposes of this discussion, we will take the following ways
of describing our relationship to the data we create, maintain
and retrieve as equivalent. A row in a conventional table, we
may say, indicates:
(i) What we
accept
as a true statement of what the object it
represents is like.
(ii) What we
agree
is a true statement of what that object is
like.
(iii) What we
assent
to as a true statement of what that object
is like.
(iv) What we
assert
is a true statement of what that object is
like.
(v) What we
believe
is a true statement of what that object
is like.
(vi) What we
claim
is a true statement of what that object is
like.
(vii) What we
know
is a true statement of what that object
is like.
(viii) What we
say
is a true statement of what that object is like.
And
(ix) What we
think
is a true statement of what that object is
like.
Whatever semantic differences there may be between
accepting, agreeing, assenting, asserting, believing, claiming,
knowing, saying and thinking—and such differences are of great
importance in such fields as epistemology, linguistics and the
foundations of logic—these differences make no difference as
far as bi-temporal data management is concerned. The funda-
mental difference for our purposes is between
ontology
and
epis-
temology
, between talk about what the world is like, and talk
about what we think it is like.
A more thorough discussion of the semantics of statements
and assertions is outside the scope of this topic, but the reader
should be aware that there is more here than meets the eye.
For one thing, assertions are not statements. They are what
philosophers call
speech acts
, ones made by means of
statements. A statement is true or false. That is a relationship
between the statement and the object
it
represents and
