What externalizes? Most talk of the externalities assumes some quantity that exists somewhere, but without a good reason to believe they exist why should we?
A simple example is the current cost of recycling plastic: it's too expensive so it won't happen. Consequently putting these on the sheet as an externalities doesn't make sense Forcing it to happen is probably nonsensical, why not fund research into plastic recycling instead instead of deadening the economy through unintended consequences?
It seems you either don't know what an externality is, or you don't understand how plastic is an externality. In the second case, I literally cannot help you. Try to imagine yourself as a member of the ecosystem which is actively collapsing? The oxygen you are breathing isn't made in a lab.
The creation, purchase, and disposal of plastic has consequences for people that are not involved in that chain, and therefore have no ability to be compensated (or in the case where those consequences produce a societal benefit, compensate) in this transaction.
This is a very common market failure. Most "transactions" actually effect everybody. One of the roles of government (and I suspect there are some radical economists that would say the only role of government) is to measure these external costs of transactions, and tax or subsidize the transactions accordingly. Externalities represent an essentially infinite amount of market failure, and the heuristics that are employed for dealing with them are almost necessarily very crude.
In the case of bottles, we are saying "Hey, we estimate the environmental damage of one plastic bottle at %d, and we are charging you that amount to sell one".
What specifically, and how large (dollars / plastic item/unit) are these externalites? If you can't describe and quantify them then there isn't an argument for compensating (taxes, bans) against them.
[0] e.g. If I dump 100 PET soda bottles into the ocean how many humans would be inconvenienced, how many fish killed? My napkin math says essentially none of either.
Dumping those plastics in the ocean begins a cycle of creating microplastics. These plastic particles are being incorporated in food chains and the ramifications of this are not understood at this time, and may take some time to figure out.
Your napkin math says this? So it must be right then... Surely all that is required for such a decision on the scale of every human doing this every year is some napkin math.
No, it's not. Napkin math is utterly useless here, and I think you don't understand utility.
Ultimately, all utility functions (strategy space to R), when integrated over the rest of time, produce either a finite value, or an infinite value. Trying to figure out which, for a given strategy, is in general undecidable.
Numbers sort of break down at this point. Or at least numbers as linear constructs. Humanity lives in a dynamical system, and as long as that dynamical system is stable enough (eigenvalues all near 1), we know from observation that evolution (in the biological sense) is capable of maintaining the invariants required to sustain human life and civilization. I will call this the flight envelope of life on earth.
This is an extraordinary gift. If I can prove that Humanity's strategy preserves these invariants, I can count on evolution to extend our presence more or less indefinitely, at least up to the point where the sun runs out of hydrogen or we are struck by some very large celestial object.
The squandering of this gift, by failing to maintain these invariants, has a literally incalculable cost. If we voluntarily exit the flight envelope of life, it is impossible to tell what will happen as a result, but it won't be as good as whatever we can get by staying in it. So my back of the napkin math says that the correct price to place on disposal of plastic into the ocean is "don't". There is no world in which the marginal utility of 50 trillion plastic bottles is greater than staying in the flight envelope.
They don't last forever, the econonmy is not going to be in its current form for even a few hundred years, and if we're going with current methods the oil will run out too.
And you didn't even give a reason that plastic would kick us out of the flight envelope if we ignore those flaws in the argument.
So your very last line is true but you have done basically nothing to demonstrate that we have to choose between the two.
You don't understand. The invariant to be maintained is the (amount of plastic in the oceans). Failing to maintain that invariant is a bad idea SIMPLY because you are failing to maintain it. Increasing the quantity of carbon dioxide in the atmosphere is a bad idea even if we have no conception of global warming.
We're failing to maintain a million randomly selected invariants, though. "I can measure it" is a terrible motivating reason to keep something the same, and it would be impossible to maintain every invariant.
So instead we should look at actual harm and/or cleanup cost.
The irony of suggesting cleanup cost here, I just don't know. Cleaning up maintains the invariant. You have successfully put the intrinsic price tag on the externality. Well done.
Please don't deliberately interpret my comment to be the weakest form.
Looking at what it would cost to clean up doesn't have to mean actually cleaning. But let's remove that part, because the important part is to look at actual harm.
Especially because if you can't tell me the relationship between plastic levels and harm, and you can't tell me how much is too much, what if I decide we've already broken the invariant and there's no point in reducing any more?
I only suggested looking at cleanup cost to get a better understanding of how to handle the harm. Not because we have a magic list of which things must be cleaned up and which things don't need to be.
Because you'd need such a magic list. Otherwise how do we know that we don't need to blow up all our houses because they're violating an invariant, or something similarly crippling? What if Earth can only safely supply 10 million humans in the long term, for a fun possible invariant.
You cannot measure "actual" harm, because the system is dynamical.
You wanted a definition of externality, I gave it to you. There's a function that gives you the upper bound on the cost of an externality, which for lack of a better term, we can call the clean up function. This is the cost of returning the system to its original state.
You don't need a magic list, you need a way of demonstrating that certain actions are within the flight envelope of the environment, ie, there is some corrective force within the environment that maintains the invariant for you, and a policy of denying all actions that do not come with such a demonstration. The list can expand as scientific understanding expands, and we are allowed some leeway by the intrinsic stability of the system. If evolution could not absorb some unexpected perturbations, we wouldn't exist in the first place, but we should treat this as a finite resource, for which we do not have an amount.
Evidence that we don't do this at all is just you being in denial about the terribleness of the human strategy.
Imagine, for metaphor, that you are in some (solar powered) alien plane, and the pilot dies. You go into the cockpit, knowing that you just have to keep the plane flying. You make a mental note that all of the instruments on the panel are fixed, and the position of all of the controls. You decide that you want to fly faster so you fiddle around with the contrls until you can tell that the landscape is going underneath you faster than it was before. You note that some instrument on the panel is increasing. Do you A) ignore it, or B) return the controls to their original state?
If you can't measure it how do you know it exists? That is at least half of my point, the other half being you can't assume a specific course of action is necessary and proper without demonstrating the harm actually occurred. That you think harm might occur is not enough, you need to show it has occurred (and can probably use proof of past harm to show that inevitable harm will occur).
Your example is disingenuous because a cockpit instrument by definition monitors something you want to pay attention to. We can measure and record many things, most of which are probably irrelevant to many problems and their solutions.
A simple example is the current cost of recycling plastic: it's too expensive so it won't happen. Consequently putting these on the sheet as an externalities doesn't make sense Forcing it to happen is probably nonsensical, why not fund research into plastic recycling instead instead of deadening the economy through unintended consequences?