Sometimes that's the reality of the situation, there are things that cannot be priced. That's why we don't consider a murder tax an acceptable way to deal with homicide.
Maybe. Maybe not. Maybe you can, but the costs to the environment involved in doing so are prohibitive. In any case, I don't think it's totally obvious that this is actually possible ATM.
> If your model contains infinities, it's automatically unhelpful; that takes you into Pascal's Wager territory
Yeah, well, reality > model. Unless we colonize space, destroying earth = infinity. So the implication of your statement is that pricing is a bad model for certain types of environmental damage. However...
> would justify draconian measures against even trivial risks of too many plastic bags.
...the realistic impact of most types of irreversible environmental damage has no known bound, but is not infinite.
Difficult-to-bound unknowns also make it impossible to quantify damages a priori at the level of detail necessary for pricing. Again, reality > model, so accurate pricing is a bad mechanism.
I think there are reasonable arguments against plastic bag bans. But trying base policy on an accurate accounting of the cost of long-term or irreversible environmental damage is a fool's errand in many cases.
(Also, note that my point is that in general, pricing environmental externalities is weird. Plastic bags aren't even nearly the best example of this, but are illustrative of the most common solution -- don't price, disincentivize.)
That doesn't sound like it justifies any one tradeoff over another, nor tell us how we should decide to.
You've heard of the precautionary principle?
Maybe, maybe not; I was responding to a poster who was justifying it on that basis.
>More generally, the language of economics ("pricing-in externalities") doesn't make sense when discussing irreversible damage to the environment:
>When you can't repair the damage, the idea of "pricing-in" externalities is just confused thinking. (You can't buy a new planet...
Well, you can repair the damage from plastic bags.
>2. For any consumer behavior that causes irrevesable damage to the environment, the cost is at once too large to quanify
If your model contains infinities, it's automatically unhelpful; that takes you into Pascal's Wager territory. If the damage is infinitely bad, then it it would justify draconian measures against even trivial risks of too many plastic bags. But however bad they are, they're not infinitely bad. Such a model would justify arbitrarily high bag fees, not some piddling ten cents with the hope of changing long-term consumer behavior.