I would say that this depends on the definition of vegetarianism you are using.  If the definition is that, at the current price, the person consumes no meat then that fifth reason does hold.

However, I see explicit vegetarianism as suggesting that a person would not eat meat even if it was provided for them for free – it is not just having zero consumption, but making it an explicit constraint.

I agree with you 100% of course, I think that the same respect for inherent uncertainty needs to be taken into consideration when setting government policy as well.

However, I think if people hold a true belief that the price of something understates its scarcity, it is a justifiable moral position to in turn cut their consumption of that product relative to what they would have consumed without holding that belief.  I see it as akin to a personal preference more than anything else.  My concern is not with the fact that they hold this position – it is with the fact that some people may try to force their moral preference on others.

As a general rule, I think it foolish for anyone to adjust their behaviour out of some categorical imperative motivation to make their choices based on what would be their personal optimum if prices refelcted all relevant scarcity information, including externalities. The reason for this is the impossibility of the environmentalist calculation; you have just as much chance of moving things in the wrong direction, given the impossibility or calculating just what equilibrium prices would be if all distortions were removed.

That aside, welcome to the reason #2 club.

“I’d suggest that the amount of subsidies in the NZ situation is fairly minimal”

Indeed, but the price of meat is largely set due to global prices, which are influenced by subsidies in Europe and the United States.  As a result, we can still say that they are underpriced in a global sense.

“I suspect that even when pricing them appropriately meat would still be affordable for many people.”

Indeed, but I suspect that the quantity of meat consumed would be lower – indicating that there is indeed an issue of allocation here.  As someone who cares deeply about economics this is an essential issue 😉

I suspect that even when pricing them appropriately meat would still be affordable for many people. I’d say bring that medium-rare steak, squeamish boy. 

I do not disagree per see – however, I would say that is consistent with revealed actions.

Many people give up red meat solely, moving towards only eating white meat and vegetables on the back of this very allocative issue.  Furthermore, some people may make the choice without understanding the full magnitude of any misallocation – and so the decision to go vegetarian can be seen as rational given limited information.

As I say in my post, I didn’t go vegetarian on the basis of sustainability – in fact, I generally don’t agree with sustainability arguments, which is why I wanted to reframe this one to think about where issues where prices could exist, and thereby put them in perspective.

This is an issue many people feel strongly about, which is fine, I see the arguments we have both made as putting this issue in context rather than disagreeing with them in any sense.

Must be making up for my lack of children.

More seriously, I’m not saying that these are the things I want to do – I’m just trying to frame the argument in a way where we can have common ground with vegetarians, so that we can then clearly figure out where the differences of opinion are 😉