Mainly by example.
(Updates give a hint as to what longer version looks like.)
Trying a thesis statement, to see if it works better than the [b] tag. Works well with goal: balance. Fixing flow later, if pilot project works out.
Point: matching properties.
Defining philosophically, psychological egoism means that 'selfless' acts have all the properties of 'selfish' acts. They are essentially the same thing. Using different words for them is akin to using different words for your left hand as opposed to your right.
Counterpoint: lay usage and communication.
Point: clear thinking.
It's unfair and ineffective to expect the lay philosopher to use words according to their underlying concepts, and as a result if you want to call your left hand a 'harble' instead I'm happy to play along. It doesn't change the fact that a harble is essentially a hand. However, for the philosopher, calling it a harble only makes it harder to think clearly about it.
Counterpoint: selflessness may still be distinguishable from selfishness.
Point: implications of matching properties.
Selfless acts may have additional properties - I don't know, I'd have to check. Right hands additionally are 'usually dominant.' This is no way makes them not a hand. Almost anything I can demonstrate about hands automatically generalizes to harbles. (I use demonstrate very deliberately. The statement is true regardless of whether you think I can demonstrate anything.)
Point: conceptual torture itself twists language.
Calling similar things by different names is what leads to me torturing language. Calling a left hand a harble quite reasonably leads to the incorrect inference about whether harbles can be dominant. Which in turn means that if I want to discuss southpaws, I first have to deal with the impression that the definition, "Southpaws are harble-dominant," is somehow a contradiction.
I would love to simply say "politicians" but I have to use things like "Republibrats and Democan'ts" because I can't otherwise count on the automatic inference that they're basically the same, nor the reverse connection that anything I demonstrate about politicians automatically applies, without reservation, to Democan'ts and Republibrats.
Update: Relevant. (Via.)
Point Zero, put into words during thinking about the third point: Aretae is committing linguistic torture by attacking linguistic torture. The idea is for philosophers not to hot-swap a new concept into a layhuman's word. However, what he objects to in practice is taking the layhuman's concept and working out what it in fact implies. (On request, I can point to specific examples of me doing this, if the coercion example below isn't clear enough.)
A word cannot both imply and not-imply a thing. To follow Aretae's model, the layhuman's meaning has to be changed to mean something else.
'Linguistic torture' is self-contradictory.
Counterpoint: there is a sophist technique very close to what Aretae points to. There's an instantly fatal counter-technique, such as described as word taboo by Yudkowsky.
First point: from my perspective, everyone engages in linguistic torture. It is impossible for you not to. I'm capable of working out what you mean, I do it all the time; the only question is whether you're capable of working out what I mean.
In math, let "X" be whatever. In philosophy, the same variable-reading skill is necessary, because the same variable-setting is necessary.
Second point, wrapping back to first:
I could use a different word for Jim than coercion.
For the sake of the example, I'll use, "moral violence is physical violence (even mild) except that necessary to prevent
First problem; explaining the definition of the thing. First problem is assuming he would even listen. Second problem, he'd likely go, "Oh, you mean coercion," and then import the extensions I was specifically trying to exclude. Third problem, assuming I managed to fix 1 and 2, is understanding what the definitions implies, which I have literally never managed to successfully transmit. Fourth problem, the argument is likely to devolve into arguing about what the definition should be; in the past this has been because the various options import various extensions, and it becomes a proxy argument about the extensions; utterly exasperating and dumbfounding, as the parties agree on which extensions are which and thus must understand what the definitions imply.
Or, you can solve all this by noting that good philosophy does not import extensions. The harder the problem, the more important it is to put all the necessary extensions into the formal intension.
E.g. Coercion in fact means what I want it to mean.
"In law, coercion is codified as the duress crime" By contrast, redressing that crime cannot be coercion; following the law can't be a crime. "Such actions are used as leverage, to force the victim", no victim, no coercion. Don't make me /wiki 'victim' to show that locked up felons are not defined as victims. Finally, "Coercion is the practice of forcing another party to behave in an involuntary manner [...] or some other form of pressure or force.", and if you follow the logic through, the intension of 'coercion' covers literally all immoral acts, and does not cover any non-immoral act. Immorality and coercion are exact synonyms; Aretae would of course disagree, but that means he thinks Wikipedia's description is simply wrong. Which in turn means he's trying to linguistically torture coercion (for example) into something other than what most Wikipedia editors think it is.
Jim's using, "Coercion is any intentional act which causes an otherwise involuntary response in another." As above, I have no problems with him using harble, and I play along. My issue is that he gets to use harble but apparently I'm held to a higher standard. Hey kids, what does it imply about me to hold me to a higher standard? Which of these implications would be opposed by the people trying to hold me to these standards?