What is coherence?

[Bill Mann]

Dear RSTlist subscribers:

I would like to start the discussion with the topic of coherence, partly because
RST has often been described as accounting for coherence.

What is coherence?

It seems to be taxonomically in the category of personal mental experiences, a
kind of impression that comes out of the process of reading a text.  We treat it
as an attribute of the text.

It seems to be an informal thing, something to be accounted for rather than a
part of an account, although it certainly could be a part of a description of
some larger phenomenon,  communication for example.

My own definition has changed a bit recently.  One component of coherence for me
is the impression that every part of the text has an evident role.  Not only
that it must have some role, but that I the reader or hearer, after some
consideration, could describe the role of any chosen part.  The opposite is the
presence of a _non sequitur_ -- a portion that does not fit, has no clear role.

I want to add to that another aspect:  A coherent text does not give the
impression that something is missing.  If we find:

"I have two reasons for saying that.  First, they try harder."  <END OF TEXT>

there is an impression of a gap.  There are many ways to produce such an
impression.

So:  Evident role for every part.  No appearance of gaps.

Is that what you think it is?

If one wishes to claim that RST accounts for coherence in some sense, it would
be good to have a clear idea just what coherence is.

Enough.  Let's discuss.

Bill Mann