But they are important if you are concerned about the role of government.

How big of a concern should this be relative to other possible concerns? (I think "what should the role of government be?" is another privileged question. What do you intend to do with an answer to this question? (I am not convinced of the value of voting.))

If I apply this principle to this author and this post, I'd wonder why take these three issues to make his point

I picked the first three things that came to my head.

Agreed, but the OP was talking about "effective altruism" , rather than about "effective morality" in general. It's difficult to talk about altruism at all except within some sort of consequentialist framework. And while there is no simple way of comparing goods, consideration of "effective" altruism (how much good can I do for a relatively small amount of money?) does force us to look at and make very difficult tradeoffs between different goods.

Incidentally, I generally subscribe to rule consequentialism though without any simple utility function, and for much the reasons you discuss. Avoiding vicious disputes between social agents with different values is, as I understand it, one of the "good things" that a system of moral rules needs to achieve.

I don't buy the assumption that seems to be implied that many arguments have to be weak and a single argument has to be strong.

Why not have many strong reasons instead of one weak reason?

Certainly for complex questions I find multi-threaded answers more convincing than single-threaded ones.

Fox over hedgehog for me.

In terms of picking a major, do something you enjoy that you can conceivably use to get a job. You can actually get a job with a philosophy degree. I did... after I quit accounting because it was too darn boring...

Koan answers here for:

What rule could restrict our beliefs to just propositions that can be meaningful, without excluding a priori anything that could in principle be true?

An important question is whether there is a net loss or gain of sentient life by avoiding eating meat. Or, if there is a substitution between different sentient life-forms, is there a net gain to quality of life?

1. Do we know where the biomass that currently goes into farmed animals would end up if we stopped using farmed animals? Would it go into humans, or into vehicles (biofuels) or into wildlife via land taken out of agricultural production?

2. Should we assume that farmed animals have a negative quality of life (so that in utilitarian terms, the world would be better if they stopped existing and weren't replaced by other sentient beings)? The animals themselves would probably not assess their lives as having negative value (as far as I'm aware, farmed animals do not attempt to commit suicide at every available opportunity).

3. Do farmed animals have a lower quality of life than animals living in the wild? Remember that nature is not a nice place either...

My personal guess is that without meat, we would end up with more humans, though mostly poorer humans. Since even the poorest humans would probably have a higher quality of life than the animals they substituted, it looks like a net gain from the point of view of total utility. But whether that is really a good thing or not may depend on whether you are a total utilitarian or an average utilitarian.

I have no interest, rational, emotional or otherwise, in funding a life for free steers in the wild.

Without engaging with any of your other points, I'd just like to point out that the OP considers the good outcome to be one where farm animals don't exist at all, rather than one where they're free in the wild. (Because if animals don't exist then they can't suffer.)

Incidentally, at the MIRI workshop, we soon started referring to the source-code-swap Prisoner's Dilemma between two modal agents as "modal combat".

Or "MODAL COMBAT!", if you prefer.

I have no argument with your desire to establish the most cost-effective way to get the most bang for your bucks. I simply do not accept the premise that it is wrong to eat meat.

Consider the life of a steer in Cape York. It is born the property of a grazier. It is given health care of a sort (dips, jabs, anti-tick treatment). It lives a free life grazing for a few hundred days in fenced enclosures protected by the grazier's guns from predators. Towards the end, it is mustered by jackaroos and jillaroos, shipped in a truck to the lush volcanic grasslands of the Atherton Tableland to be fattened up. On its last day, it is trucked to an abattoir to be stunned and killed.

If the grazier did not exist the steer would not exist. Now I could make some argument about 'utility' but I won't. And indeed there is a distinction between the factory farming you object to (grain-fed beef) versus older ways (grass-fed beef).

I would not like to be given this treatment myself but I am not a domesticated animal. I am not a beast or a dumb animal. I am a top predator. We have evolved to prefer meat and vegetables in our diet. We have arranged the ecosystem to satisfy our desire for meat. I value steers dead, butchered and then grilled or roasted. I have no interest, rational, emotional or otherwise, in funding a life for free steers in the wild.

A fundamental political problem for vegan advocacy is that people enjoy meat and that it is 'natural' to eat it. Now being natural is not a right maker but going against nature and being dependent on vitamin supplements to avoid anemia is not a right maker either. Stick people in the bush with no food and a bow and arrow and they will figure out how to shoot cute kangaroos and koalas quick smart rather than starve. Submit homo sapiens to enough stress and those predator instincts and drives that are suppressed in the civilized ecosystem come to the fore.

Desire drives us all. Argument that goes against basic human desire goes uphill. Vegetarian advocacy has been around for a long time (since Buddha, Mahavira) as have the moral arguments. Alas, human moral functionality is limited. Your research dollars would be better spent on finding an ethical alternative to meat that tastes way better than soy burgers. When vegans can provide a product that rivals that of the butchers in taste and appeal, then they will succeed.

Until then, they are a tiny minority that get recruits and suffers defections at more or less similarly measurable rates. In the meantime, I prefer organic and free-range products.

That seems to imply we understand our rationality...

You could also, in principle, have a utilitarianism that gives unequal weights to different people. I've asked around here for a reason to think that the egalitarian principle is true, but haven't yet received any responses that are up to typical Less Wrong epistemic standards.