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Re: Philosophies for Character Ordering
----- Original Message -----
From: "Mike Milbocker" <firstname.lastname@example.org>
> David Marjanovic wrote:
> >>Ordering only means to arrange the states of a character in a line. It
> does not make any assumptions about which end of
> the line is the plesiomorphy. This is for the outgroup to decide. [...]
> It's exactly the same as with binary characters.<<
> Well to be literal, it can't be exactly the same as binary characters,
> otherwise there would be no advantage to using ordered states.
The alternative to "ordered multistate" is "unordered multistate" and not
"binary". Ordering isn't applicable to characters with just 2 states.
> It's the line itself, as well as the direction of the line that is encoded
> with assumptions about evolution, albeit quite reasonable assumptions.
Yes; but you wrote that ordering makes assumptions on both of these things,
while it just makes assumptions about the first.
> If one is going to allow fewest transformations to order the states, why
> use stratigraphic data, spatial proximity, fitness of preservation.
Using stratigraphy, at least, would be to make an assumption about the
direction of the line _in addition to_ make assumptions about the positions
of the characters on the line.
> Quite reasonably, one could devise ordering paradigms to
> encode Bakker's entire Heresies into a set of characters.
How do you mean?
> I'm not objecting to its use, I'm just cautioning that if one
> uses ordered states one can no longer claim that the cladogram is the
> simplest structure depicting character associations.
It isn't supposed to be this. It's supposed to depict the simplest
hypothesis about the _evolution_ of said character associations.
> It's predictive power
> will be dependent upon the reality of the ordering assumptions.
> And I would hope such assumptions would be clearly stated.
Fortunately there's a trend to do just this.