[EM] A few concluding points about SFC, CC, method choice, etc.

[Michael Ossipoff]

Kevin and Chris posted their criteria that they incorrectly claimed 
equivalent to SFC.

These same alternative "SFCs" have been posted to EM before and thoroughly 
discussed before.
In fact, we've been all over this subject before.

Though Chris's and Kevin's criteria clearly are not equivalent to SFC, maybe 
someone could write a votes-only cirterion that is. First of all, what's 
this obsession about "votes-only"? Though my IIAC is votes-only, everyone 
invokes a preference-based IIAC (though no one defines it). The Condorcet 
Winner (CW) is defined in a preference-based way.

Anyway,  maybe someone could write a votes-only criterion equivalent to SFC. 
It would be an inelegant, arbitrary, grafted hodgepodge. As I said, we’ve 
been over this. For instance, since no nonrank method can meet SFC anyway, 
someone could stipulate, in their criterion’s premise or requirement, that 
the method being tested be a rank method. If the stipulation is in the 
premise, then the criterion applies only to rank methods. It won’t rate 
Condorcet better than Plurality, but I will compare Condorcet to IRV or 
Borda or Dodgson or Copeland. I’m not saying that wouldn’t be of any use at 
all, to compare the rank methods, but my criteria apply to and compare all 
the methods. If the stipulation is in the criterion’s requirement, then it 
arbitrarily and dictatorially says that nonrank methods fail the criterion. 
Now it applies to all methods. But not in the seamless way that my criteria 
apply to all methods.  You must agree that there’s something a little
Worthless-sounding about a criterion that says “Nonrank methods fail this 
criterion because I say so.”

So, even if someone could write a vctes-only SFC-equivalent, it would be 
offensive to me, for the above reasons, and I wouldn’t use it.

Now, quite aside from that,  the efforts to write a votes-only equivalent 
criterion seem motivated by a desire to not say  things that happen to be 
what I want to say. I want SFC to be about the fact that that majority, 
because they all prefer the CW to Y, and because there’s no falsification 
(on a scale sufficient to change the outcome), can defeat Y by doing nothing 
other than voting sincerely.

To say it in a way that doesn’t say that wouldn’t be SFC. If someone wrote 
such a criterion, then I’d recognize it as a _test_ for SFC compliance, but 
not as SFC. When I say that a method passes or fails SFC, and someone says 
“What’s that?”, then I want to tell them the SFC described in the paragraph 
before this one, the one that relates to the CW,  no need for other than 
sincere  voting by the majority and non-falsified voting by everyone else. 
If I worded it like Kevin or Chris, it wouldn’t be self-evident why it’s 
desirable to meet that criterion.

Someone could suggest that I use an alternative as the criterion, and save 
my SFC as a justification. No, I want the criterion’s value to be 
self-evident. As I said, some more convenient equivalent could be used as a 
test, but not as the main definition, the one that is offered or featured.

The same could be said for my other defensive strategy criteria. There are 5 
of them: FBC, SFC, GSFC, WDSC and SDSC. The latter four are the majority 
defensive strategy criteria.

As I said (buried in a long reply), the defensive strategy criteria are what 
I have to say about single-winner voting systems. So, regarding SSD vs. RV, 
what I have to say is: SFC,. GSFC, & SDSC.

Another thing: This issue about ways of defining a criterion isn’t only 
about my defensive strategy criteria. It applies likewise to popular 
criteria. Of my defensive strategy criteria, only FBC has any popularity.

For instance, the issue applies to Condocet’s Criterion, which, I claim (and 
have long claimed) is nonsense as it’s usually defined. In some versions it 
applies only to rank methods. In some versions it arbitrarily stipulates 
that only rank methods pass it. My own wording of CC is the only one that is 
any good.

Some people have expressed discomfort with a criterion that mentions 
preference (but the same people don’t seem to have a problem with a 
preference-based IIAC (though I’m not aware of one that is actually 
defined).

A few years ago I posted to EM a precise abstract definition of preference. 
But I also told why no definition of it is needed. None is needed because, 
whatever you think “prefer” means, it means the same thing  whenever used, 
in the criterion and in the statement of a failure example. It therefore 
doesn’t matter if “prefer” means anything at all. One could instead use some 
fanciful made-up verb from Lewis Carroll, such as “outgribe” (which Carroll 
uses only in its strong-irregular past tense,  “outgrabe”.

Much better people than Warren  have tried to find fault with the defensive 
strategy criteria. They’re battle-tested.


Mike Ossipoff