[EM] Why the concept of "sincere" votes in Range is flawed.

[Kristofer Munsterhjelm]

Jonathan Lundell wrote:
> It's a reason that "(in)sincere" isn't very good terminology for 
> everyday use; likewise "manipulation". They're fine terms when 
> well-defined and used in the context of social choice theory, but they 
> carry a lot of baggage. A voter is, in my view, completely justified in 
> ignoring the name of the election method ("approval", for instance) and 
> the instructions (vote in order of preference) and casting their vote 
> strictly on the basis of how the ballot will be counted.
> 
> (Which is why I'm partial to ordinal systems; it seems to me that I as a 
> voter can pretty easily order candidates without considering strategy, 
> whereas the decision of where to draw the line for Approval, or how to 
> assign cardinal values to candidates, explicitly brings strategy into 
> the picture.)

For ordinal systems, it's pretty easy to consider what a honest ballot 
would be, assuming a transitive individual preference. "If A is better 
than B, A should be higher ranked than B". It's not so obvious for 
cardinal systems. What do the points in a cardinal system mean? We can 
get some measure of a honest ballot by transporting an ordinal ballot 
into a cardinal ballot: if you prefer A to B, A should have a higher 
score than B. But other than that, what can we do? This seems to be a 
problem of cardinal systems in general, not just a particular 
implementation like Range (or Approval, if you consider Approval Range-1).

Thinking further, it would seem that cardinal systems can solve it in 
two ways. Either the points are in reference to something external ("how 
much would I like that X wins in comparison to that nothing changes from 
status quo"), or it refers to a subjectively defined unit ("how much do 
I 'like' X" for an individual definition of "like"). I think ratings, as 
commonly (and intuitively) used, are of the second part, but that leads 
to problems with the aggregation of the points. If one voter likes many 
things and another likes only a few, how do you compare the two 
preferences? Ranking gets around that since it only asks about relative 
information (though one could argue there's a very weak form of this 
problem with equal-ranking; how different does your opinion have to be 
of two candidates before you no longer equal-rank them?).

I guess what I'm trying to say is that the problem of discerning a 
honest vote from a strategic (optimizing) one seems to be inherent to 
all cardinal methods, because we can't read voters' minds. That is, 
unless the external comparison can be made part of the ballot itself.