He begins by complaining that "Singer's arguments are based on utilitarian premises." This is a common mistake. Singer appeals to principles like the equal consideration of interests -- you shouldn't arbitrarily favour one being's interests over the equally strong interests of another -- and that we shouldn't harm others for the sake of morally trivial benefits to ourselves. These principles are of course compatible with utilitarianism, but you don't have to be a utilitarian to accept them. Their appeal should be plain to any minimally decent person. (Singer would be a much less accomplished applied ethicist if his arguments merely took the form, "Utilitarianism implies P. Utilitarianism, therefore P"!)
Furrow's first argument is that, according to utilitarianism, "any loss in the quality of lives in a population can be compensated for by gains in the quantity of a population." Furrow here assumes the Total view of population ethics, which is controversial even amongst utilitarians, let alone everyone who might find Singer's applied principles plausible. But even more importantly, such "compensation" is obviously only possible when the lives in question are positive on net. Whereas the big concern about factory farming [esp. of pigs and chickens] is that it imposes such immense pain and suffering that the animals have negative welfare, such that they'd be better off not existing at all. Increase the quantity of lives not worth living, and the total outcome just gets all the worse!
(Eating meat from humane-raised animals, by contrast, seems fine to me -- and if I recall correctly, Singer agrees in principle, but has practical concerns about scalability and such.)
Furrow's second argument:
The logical result of utilitarianism is that all civilization may be unwarranted if the cost to animal suffering is sufficiently great—a repugnant conclusion indeed.
Is the conditional really repugnant? Isn't there some amount of suffering (imagine galaxies and upon galaxies filled with unremitting screams and agony) that would be too great a cost? Of course, I don't find it remotely plausible that civilization necessitates such great costs (out of proportion to its benefits). It would be repugnant if it did. But the repugnance would indicate a problem with civilization, not with a moral code that was at least capable (in these most extreme of circumstances) of condemning it!
[I]t is assumed that growing non-meat foods causes no pain or suffering. But of course that is not true. The planting and harvesting of crops destroys massive numbers of sentient creatures and their habitats.
The crucial claim is just that veg*n food causes less pain and suffering. Factory farmed animals significantly increase the demand for crops (needed, in inefficient proportions, for their feed). So this is all the more reason to think there are strong moral reasons to reduce the amount of (factory-farmed) meat in our diets. (Again, meat from free-grazing sources is a different matter.)
[P]ain suffered without the explicit memory of it or reflective doubts about its meaning seems less "painful" than human pain which has these psychological aspects. [...] From the fact that animals experience pain, Singer infers they have interests. But until we have a clearer understanding of animal psychology it isn't obvious what kind of interests animals have [...] If animals have interests independently of their awareness of those interests, then we would be forced to admit that plants have interests as well. Should we refrain from eating plants? Clearly we are in the realm of the absurd.
Absurd indeed. You can't move from "maybe pain is slightly less bad for non-rational beings" to "it's not obvious that pain matters at all for non-rational beings". Otherwise you're in baby-torturing territory. (This is why it's confused to write "human" instead of "rational being". Not all humans are more cognitively sophisticated than all non-human animals.)
Finally, Furrow's central argument:
But animals cannot have moral rights [or interests?], simply because the treatment of animals falls outside the scope of our core understanding of morality. Morality is not a set of principles written in the stars. Morality arises, because as human beings, we need to cooperate with each other in order to thrive. [...] Our flourishing does not depend on getting cows, tigers, or shrimp to trust us or we them, and thus we have no reciprocal moral relations with them. [...] There may be environmental reasons to refrain from eating meat but no moral reasons based on the interests of animals.
Contrary to this Contractarian conception, it is not a precondition of your mattering morally that your cooperation would be useful to me. Nazis cannot excuse their behaviour by pointing out that their flourishing doesn't depend on getting oppressed minority groups to trust them (even if mutual cooperation would actually have been better for them, just imagine a case where this isn't so). Furrow's ultimately egoistic "core understanding of morality" isn't mine, and I hope it isn't yours.
Furrow wraps up:
This is not to say we should be cruel to animals, lack empathy for them, or ignore their welfare. The reason is not that they have rights. Rather it is because cruelty is a character flaw that we should strive to overcome. But our moral energy is not infinite. The humane treatment of animals is one among many moral projects we should undertake, but it has no special priority over the many more pressing human needs that cry out for our attention. It is often assumed that vegetarians have the moral high-ground. [...] But there is no moral obligation to refrain from eating meat and thus no moral high ground to occupy.
I'm confused. There are "no moral reasons based on the interests of animals", but we "should not... ignore their welfare." Why not? Because it would be "cruel" (why? ignoring the morally irrelevant "interests" of plants isn't), which is a "character flaw". Never mind others' suffering, what really matters is that we improve ourselves. This is a "moral project we should undertake", but achieving it won't actually lead you to "moral high ground", so maybe don't bother after all.
Colour me unimpressed. (And I'm not even a vegetarian.)