Re: Mixing OO and DB

On Feb 17, 4:27 am, JOG <j..._at_cs.nott.ac.uk> wrote:
> On Feb 15, 2:31 am, David BL <davi..._at_iinet.net.au> wrote:
> > On Feb 14, 10:38 pm, JOG <j..._at_cs.nott.ac.uk> wrote:
> > > On Feb 14, 3:52 am, David BL <davi..._at_iinet.net.au> wrote:

> > > "todays lottery numbers: 23, 34, 17"
> > > "experimental results: 23, 34, 17"
>
> > > All written down on a bit of paper - same values discussed, but
> > > different data. Agree or disagree?
>
> > I agree. Yes, same values but different data
>
> > > I ask this because if we can distinguish data and values, we must then
> > > determine /how/ they are different. You state it is by "encoding" but
> > > the two lines above are encoded in the same manner as far as I am
> > > concerned, so that cannot be the difference between the two concepts.
> > > That is unless your "Encodings" equates to my notion of "Facts", and
> > > we are thus agreeing loudly, using different definitions of those
> > > terms.
>
> > They are the same values and they are encoded in the same manner.
> > However they are distinct appearances, hence distinct data.
>
> Ok, so we're agreed at least there. Same values with the same
> encoding. Yet the first datum is different to the second. The logic
> below therefore follows:
>
> 1) The two items of data discussed have the same values and same
> encoding.

I think this should say "manner of encoding"

> 2) The two items of data can obviously be distinguished (we are agreed
> they are not the same data).
> 3) Therefore a datum must possess some attribute outside of its values
> and encoding.

Again, actually should say "manner of encoding".

> What one /calls/ that extra component is debatable (context,
> description, etc), but I cannot see anyway around the above logic - in
> fact I feel like it is an incredibly strong argument. It starts with
> agreed observations, followed by the application of the law of
> indiscernibility of identicals.
>
> If you can see a hole in it then I'm sure you'll let me know ;)

I agree that a datum must possess some attribute outside of its values and manner of encoding.

[snip]

> > > But you are already assuming it is data in the first step. I say its
> > > not, and cannot follow why you would think it is. Like a "22". That's
> > > not data but, if I was a numerologist say, I would still find the
> > > value interesting.
>
> > I keep thinking you're ignoring my qualification that it is the
> > appearance of a value that counts as data, not the value itself.
>
> Not my intention to ignore it, but I have been wary of getting into a
> more handwavy discussion about nominalism, universals, formalism etc,
> etc. However, I hope to have shown above that saying data is the
> merely appearance of a value (and that may well be part of it) is
> insufficient, and that a datum is made up of the 'appearance of
> values' /plus/ something else.

I'm afraid this is where our thinking diverges!

I'll use an analogy. Consider a forest (ie set of trees) where each tree is comprised of a set of nodes plus a set of edges. Each node appears in exactly one tree. Therefore there is a mapping from node to its containing tree. By your reasoning you would say that a node is made up of itself /plus/ something else (such as the tree that it resides in). Now what exactly does "plus" mean? If it means "union" we will find that the nodes of a tree are indistinguishable (because their identity is tied to the tree in which they appear). The problem gets even worse because all the trees belong to the same forest.

My point is that it's fair and reasonable to identify a part of a composite and talk about "it" by externalising everything else that's around it. This principle is necessary for reductionism. It is justifiable to the extent that the boundary separating inside from outside is well defined. Received on Mon Feb 18 2008 - 08:20:21 CET