Honestly @Postmodern Beatnik I'm just exhausted by the conversation. Everything is such a fight with it. I wouldn't mind if the fights were about the overall points or the arguments I'm making but they're often not.

The problem is that the example is bad. — Postmodern Beatnik

Fine replace it with debeaking, I don't care, it doesn't effect the argument at all. Is it really relevant whether letting a couple cows out in the afternoon is considered a personal practice or a farming practice?
Maybe you see this as clarification, to me it comes off petty and irrelevant. There are productive ways of clarifying arguments and unproductive ways. If your going to write most a paragraph explaining how I was incorrect by not placing the words 'food consumption' in between the words 'non-vegan practices', when the actual point was entirely clear to you, well...
Maybe we will have better luck in another thread.

And yes, much of this particular thread felt like sparring.

Edit: Btw, in the other thread you pretty much didn't disagree with me at all.

Well could you think of another possible way that some gratuitous suffering could be prevented? — shmik

I would respond in much the same way that Postmodern Beatnik has, insofar as this argument is limited to a particular type of gratuitous suffering that can only be remedied by abstaining from the behaviour that necessitates the eventual slaughter of nonhuman animals. If the intentional killing itself can be regarded as gratuitous suffering, then no matter what steps have been taken to reduce suffering prior to the slaughter, the obligation to prevent gratuitous suffering will be left unfulfilled. Indeed, some of the gratuitous suffering can be prevented through better treatment prior to slaughter, but if slaughter is gratuitous suffering then one will have assess the means by which the gratuitous suffering of the slaughter can be prevented, if at all.

There is room to doubt that the intentional killing of nonhuman animals constitutes gratuitous suffering. The knowledge claim aims to address that doubt; specifically: If some nonhuman animals are sentient and food production practices would constitute gratuitous suffering in humans, then food production practices constitute gratuitous suffering in some nonhuman animals.

This establishes the metric by which we can judge gratuitous suffering in nonhuman animals and is bolstered (or ignored as the case may be) by a risk-averse assumption. We don't know what is going on in the minds of animals, but it's possible that sentience is a necessary and sufficient condition for the capacity to experience gratuitous suffering. If the moral obligation holds (i.e., If any gratuitous suffering is preventable, known and the cost to prevent said gratuitous suffering is reasonable, then it is wrong to allow said gratuitous suffering) then the next step in ascertaining moral obligation is to identify where the conditions are satisfied.

Knowledge: Is there any reason to think that food production practices are capable of producing gratuitous suffering? Well if it would constitute gratuitous suffering in humans, then it is possible that the practices constitute gratuitous suffering in nonhuman animals and by the risk-aversion principle we say that it does constitute gratuitous suffering in nonhuman animals.

What does cruelty have to do with it? The issue was that it caused gratuitous suffering. So you'd need to show that animals suffered gratuitously by being swiftly killed. Furthermore, I think the comparison with humans fails as it seems unlikely that the friends and families of the to-be-killed animal would suffer. — Michael

This comment is out of place because a built-in condition of the argument is to consider what would be gratuitous suffering in humans. That comparison is the basis for the knowledge claim, and part of the gratuitous suffering of intentional killing is the suffering felt by the animals that have relationships with the slaughtered animal (and they do have relationships). If the cruelty of the intentional killing is part of the judgement of why it would constitute gratuitous suffering in humans, then that same judgement applies in some degree to nonhuman animals (with the proviso that the nonhuman animal has a minimal physiological and neurological capacity for said suffering). The appeasement of our moral conscience by claiming it "unlikely" is too weak to ignore a serious moral obligation. I would take the risk-averse assumption over the "unlikely" assumption in case it turns out we reached too far with the obligation and aimed to eliminate suffering that wasn't present rather than not reach far enough and continue to cause preventable gratuitous suffering because of limited understanding or wishful thinking.

Reasonable cost: I have limited the cost to be acts of omission rather than acts of commission as previously stated. I feel that's a fairly reasonable cost.

Prevention: The gratuitous suffering of food production practices includes but is not limited to the intentional killing of nonhuman animals (see knowledge). The prevention must aim at all gratuitous suffering and may require multiple obligations, As it turns out, the argument states that gratuitous suffering can be prevented by a single (in)action: gratuitous suffering caused by food production practices is preventable if and only if it is possible to adopt a vegan diet. Other actions can reduce gratuitous suffering caused by food production practices but only one is capable in itself of preventing the gratuitous suffering caused by food production practices.

This comment is out of place because a built-in condition of the argument is to consider what would be gratuitous suffering in humans. — Soylent

And I question your claim that what would cause gratuitous suffering in humans would cause gratuitous suffering in non-human animals.

That comparison is the basis for the knowledge claim, and part of the gratuitous suffering of intentional killing is the suffering felt by the animals that have relationships with the slaughtered animal (and they do have relationships).

A human doesn't suffer simply because their relative or friend has been killed. They suffer if they're of the understanding that their relative or friend has been killed. So even if we were to grant that what would cause gratuitous suffering in humans would cause gratuitous suffering in non-human animals, for the comparison to work it must be the case that the animal is of the understanding that their relative or friend has been killed. So one must show that a) an animal is capable of such an understanding and that b) the animal has such an understanding. The second can be avoided simply by ensuring that the slaughter happens out of sight and hearing of other animals (and so the first wouldn't be relevant, even if true).

As it turns out, the argument states that gratuitous suffering can be prevented by a single (in)action: gratuitous suffering caused by food production practices is preventable if and only if it is possible to adopt a vegan diet.

As I've said before, this is unclear. Consider, "the boulder is movable if and only if it is possible to remove the obstacle". Let's assume that it is wrong to allow the boulder to remain unmovable. Does it then follow that everyone who can remove the obstacle must remove the obstacle? What if the strength of one is sufficient? Surely once that one person has removed the obstacle then no other person is obligated to remove the obstacle? Or what if the strength of everyone is necessary? But if one person refuses to help remove the obstacle then are the others obligated to try to remove it alone, despite the fact that it's a futile gesture?

If you want as a premise "for any person, if that person can prevent gratuitous suffering then that person ought prevent gratuitous suffering", and if you want as the conclusion "for any person, if that person can adopt a vegan diet then that person ought adopt a vegan diet" then you must have as the second premise "for any person, that person prevents gratuitous suffering if and only if that person adopts a vegan diet". Is this the premise you're willing to use?

And I question your claim that what would cause gratuitous suffering in humans counts as gratuitous suffering in non-human animals. — Michael

I question it too. As mentioned to Postmodern Beatnik, I'm not prepared to defend this claim beyond what I believe is intellectually honest but I would prefer to have grounds to defeat it rather than a mere unsupported assertion that it is dubious. What can you point to that would indicate a divergence between the capacity to experience gratuitous suffering in humans and nonhuman animals? More specifically, is that divergence significant to gratuitous suffering caused by food production practices such that what would constitute gratuitous suffering in humans should not be considered to constitute gratuitous suffering in nonhuman animals in relation to food production practices.

it must be the case that the animal is of the understanding that their relative or friend has been killed. So one must show that a) an animal is capable of such an understanding and that b) the animal has such an understanding. The second can be addressed simply by ensuring that the slaughter happens out of sight and hearing of other animals. — Michael

I'm not sure this is the cause of the gratuitous suffering or if it has to be that strong. Is it conceivable a human would still suffer without the specific understanding that a relative or friend has been killed? In humans it's sufficient to recognize that the relationship has ended (by some unknown mechanism) and that recognition per se causes suffering. The suffering of the loss of a relationship that we can identify by virtue of our humanity can in turn be categorized as gratuitous (i.e., unjustified) if the suffering is caused by the intentional actions of moral agents without sufficient warrant. The nonhuman animal doesn't need the capacity to recognize its own suffering as gratuitous, the judgement of gratuitous comes from moral beings on the basis that the suffering is not morally permissible (as per the conditions of the moral obligation). The nonhuman animal doesn't have to identify the cause of or be able to articulate the deep emotional attachment that causes suffering in order to recognize that the nonhuman animal is suffering.

I'm not prepared to defend this claim beyond what I believe is intellectually honest but I would prefer to have grounds to defeat it rather than a mere unsupported assertion that it is dubious. — Soylent

That's not the way the burden of proof works. If you use a premise to make an argument then you must defend that premise; it is not the burden of the other person to disprove it.

What can you point to that would indicate a divergence between the capacity to experience gratuitous suffering in humans and nonhuman animals?

The issue isn't over whether or not there is a divergence between the capacity to experience gratuitous suffering in humans and non-human animals; the issue is over whether or not there is a divergence between the cause of gratuitous suffering in humans and non-humans.

As an example, feeding capsaicin to a human will cause the human to suffer but feeding it to a bird won't cause the bird to suffer. Therefore that it is wrong to feed capsaicin to a human (on the grounds that it causes suffering) is not that it is wrong to feed capsaicin to a bird (on the grounds that it causes suffering).

The nonhuman animal doesn't need the capacity to recognize its own suffering as gratuitous, the judgement of gratuitous comes from moral beings on the basis that the suffering is not morally permissible (as per the conditions of the moral obligation).

But does it suffer at all, let alone gratuitously? Is the animal capable of recognizing this lost relationship, and if so, does it care?

Furthermore, this highlights another issue with your argument. You define gratuitous suffering as "suffering that is not morally permissible". This then means that premise 2 amounts to "if food production practices would constitute morally impermissible suffering in humans then food production practices constitute morally impermissible suffering in sentient non-human animals". But where's the justification for this? Even if you can show that humans and non-human animals have the same capacity to experience suffering, and even if you can show that food production practices cause non-human animals to suffer, you haven't shown that such suffering in non-humans animals is morally impermissible.

I might say that the suffering caused to humans by food production practices is only morally impermissible (i.e. gratuitous) because they are human, and obviously this reasoning can't apply to non-human animals. So what, aside from our humanity, would make such suffering morally impermissible?

That's not the way the burden of proof works. If you use a premise to make an argument then you must defend that premise; it is not the burden of the other person to disprove it. — Michael

That's only true if i) I feel like the argument needs to be defended and ii) the person opposing the argument hasn't issued a claim that itself needs defense. I have no interest in defending the argument but I am curious what reasons a person gives in response to the argument aside from, "I don't like it". The rebuttal is more interesting to me than the support (unless someone feels compelled to support the argument). I've pondered this argument for a while and I have rejected it too, but that doesn't mean I was right to reject it unless I have reasons for that rejection.

The issue isn't over whether or not there is a divergence between the capacity to experience gratuitous suffering in humans and non-human animals; the issue is over whether or not there is a divergence between the cause of gratuitous suffering in humans and non-humans. — Michael

This might be splitting hairs but your counterexample of capsaicin is duly noted. Is it fair to say a capacity is the potential and the cause is the capacity realized?

Even if you can show that humans and non-human animals have the same capacity to experience suffering, and even if you can show that food production practices causes non-human animals to suffer, you haven't shown that such suffering in non-humans animals is morally impermissible. — Michael

Suffering is morally impermissible and gratuitous if it is known, preventable, and preventable at a reasonable cost. The argument itself aims to show that the suffering of nonhuman animals by food production practices is gratuitous suffering and morally impermissible. P2 is a hypothetical premise introduced with the intention to demonstrate that conclusion and taken along with the other premises shows that food production practices is morally impermissible and obliges a vegan diet.

I take your objection to be the use of "gratuitous" to describe the suffering in the early premises and the appearance of begging the question. I used the term gratuitous to distinguish it from other suffering, where only gratuitous suffering obliges (in)action. It doesn't make much sense to construct a moral argument to talk about non-gratuitous suffering because such suffering is outside the scope of knowledge, potency or too burdensome. I consider it a bit of a trivial distinction, but useful to remind the reader that the only suffering I am talking about falls within that range. If the argument succeeds (and I suspect it doesn't), it only applies to gratuitous suffering.

Suffering is morally impermissible and gratuitous if it is known, preventable, and preventable at a reasonable cost. — Soylent

This is confusing. Are you defining "gratuitous suffering" as "morally impermissible suffering" or as "known and preventable (at a reasonable cost) suffering"? Or is its meaning something else?

This is confusing. Are you defining "gratuitous suffering" as "morally impermissible suffering" or as "known and preventable (at a reasonable cost) suffering"? Or is its meaning something else? — Michael

Gratuitous suffering = morally impermissible suffering. Suffering is morally impermissible by the following conditions: known and preventable (at a reasonable cost).

Definition of gratuitous suffering: If suffering is preventable (at a reasonable cost) and known, it is wrong to allow said suffering. Suffering that is wrong to allow is gratuitous suffering.

Gratuitous suffering is morally impermissible by virtue of being gratuitous suffering, and established by the conditions above. By the transitive property:

P1 If any gratuitous suffering is preventable (at a reasonable cost) and known, it is wrong to allow said gratuitous suffering. (trivial moral claim)

Gratuitous suffering = morally impermissible suffering. Suffering is morally impermissible by the following conditions: known and preventable (at a reasonable cost). — Soylent

If gratuitous suffering is preventable by definition then the premise "gratuitous suffering caused by food production practices is preventable if and only if it is possible to adopt a vegan diet" fails. Gratuitous suffering does not depend on something else (e.g. the possibility to adopt a vegan diet) to be preventable.

It's like saying "bachelors are unmarried men if and only if it is possible to X" (where "bachelors" is defined as "unmarried men").

Perhaps you meant to just say "suffering caused by food production practices is preventable if and only if it is possible to adopt a vegan diet"?

If gratuitous suffering is preventable by definition then the premise "gratuitous suffering caused by food production practices is preventable if and only if it is possible to adopt a vegan diet" fails. Gratuitous suffering does not depend on something else (e.g. the possibility to adopt a vegan diet) to be preventable. — Michael

Huh?

It's defined as preventable only insofar as it has some means that satisfies the condition of prevention. Whether food production practices is gratuitous suffering relies on whether there is a means for the prevention of said suffering (e.g., a vegan diet). Food production practices is gratuitous suffering because the suffering can be prevented iff it is possible to adopt a vegan diet. If it was impossible to prevent the suffering of food production practices, that suffering would be considered unpreventable and morally permissible.

It's like saying "bachelors are unmarried men if and only if it is possible to X" (where "bachelors" is defined as "unmarried men"). — Michael

I think it's more akin to the following:

bachelors are called such iff they are men and remain unmarried. (where "bachelors" is defined as "unmarried men").

Maybe you're right though. I regarded the constant back and forth with the definition of gratuitous suffering at each stage needlessly cumbersome, but it might be helpful for clarification.

I think it's more akin to the following:

bachelors are called such iff they are men and remain unmarried. (where "bachelors" is defined as "unmarried men"). — Soylent

So by this you mean "those men who are called bachelors are called bachelors if and only if they are unmarried men"?

Then consider: "that suffering which is called gratuitous is called gratuitous if and only if it is possible to adopt a vegan diet". How does one then conclude "one ought adopt a vegan diet" from that?

Then consider: "that suffering which is called gratuitous is called gratuitous if and only if it is possible to adopt a vegan diet". How does one then conclude "one ought adopt a vegan diet" from that? — Michael

One doesn't, that is only a single premise and the claim that "one ought to adopt a vegan diet" follows from many premises and conclusions when taken together.

I'm looking at P9.

"If it is wrong to allow gratuitous suffering caused by food production practices, and gratuitous suffering caused by food productions practices is preventable if and only if a vegan diet is adopted, then a vegan diet ought to be adopted."

I'm questioning how "it is wrong to allow preventable suffering caused by food production practices" and "that suffering caused by food production practices which is called gratuitous is called gratuitous if and only if it is possible to adopt a vegan diet" imply "a vegan diet ought to be adopted". It certainly doesn't seem to be the case that "a vegan diet ought to be adopted" is derived from the other two sentences.

C5 is actually embedded in P9.

P9 /P10 should read something like: "The only way to prevent the gratuitous suffering caused to animals in the food production practices is to take animals out of food production. "

"The only way to remove animals from food production is to eat a diet which doesn't require them to be part of the process (i.e vegan)."

C5: "If it is wrong to allow the gratuitous suffering (of animals) in the food production practices, a vegan diet ought to be adopted.

I'm questioning how "it is wrong to allow preventable suffering caused by food production practices" and "that suffering caused by food production practices which is called gratuitous is called gratuitous if and only if it is possible to adopt a vegan diet" imply "a vegan diet ought to be adopted". It certainly doesn't seem to be the case that "a vegan diet ought to be adopted" is derived from the other two sentences. — Michael

I would caution against reducing gratuitous suffering to "preventable suffering". That suffering is preventable is a necessary but not sufficient condition for suffering to be judged as gratuitous.

P9 is a hypothetical so I'm not sure why you're trying to read it as several independent claims absent the hypothetical operator. It's more of a hypothetical move from the trivial moral claim in P1 to the specific means established by P6. More succinctly, if it morally impermissible to allow some outcome and the only way to prevent that outcome is performing or abstaining from a specific action, then it is morally impermissible not to perform or abstain from the specific action.

Where gratuitous suffering does not have a one-to-one relationship with the means of prevention, the prevention does not oblige a specific performance or abstaining of action. A vegan diet (i.e., the means of prevention) is only obligated if it has a one-to-one relationship with the prevention of gratuitous suffering caused by food production practices. The conclusion that "one ought to adopt a vegan diet" follows from the entire argument before it and not a single premise taken in abstraction.

P9 is a hypothetical so I'm not sure why you're trying to read it as several independent claims absent the hypothetical operator. — Soylent

It's in the form "if X and Y then Z". I'm questioning this material implication. If the material implication fails then the premise fails, and if the premise fails then the argument fails.

More succinctly, if it morally impermissible to allow some outcome and the only way to prevent that outcome is performing or abstaining from a specific action, then it is morally impermissible not to perform or abstain from the specific action.

But the actual phrasing is "X is preventable iff Y is possible". Did you actually mean "X is prevented iff Y"?

The conclusion that "one ought to adopt a vegan diet" follows from the entire argument before it and not a single premise taken in abstraction.

I'm not questioning C5. I'm questioning P9. In P9 you say that "one ought adopt a vegan diet" is implied by "it is wrong to allow gratuitous suffering" and "gratuitous suffering is preventable iff it is possible to adopt a vegan diet". I'm questioning this.

A vegan diet (i.e., the means of prevention) is only obligated if it has a one-to-one relationship with the prevention of gratuitous suffering caused by food production practices.

Then if it can be shown that I can't prevent gratuitous suffering by adopting a vegan diet then I am not obligated to adopt a vegan diet.

So, if I adopt a vegan diet will gratuitous suffering be prevented? Well, no. The premise "If Michael adopts a vegan diet then gratuitous suffering will be prevented" is false (my adoption of a vegan diet won't entail a change in food production practices), therefore one cannot derive "Michael ought adopt a vegan diet" from it (in conjunction with the premise "Michael ought prevent gratuitous suffering").

I would caution against reducing gratuitous suffering to "preventable suffering". That suffering is preventable is a necessary but not sufficient condition for suffering to be judged as gratuitous.

Then what are the necessary and sufficient conditions?

But the actual phrasing is "X is preventable iff Y is possible". Did you actually mean "X is prevented iff Y"? — Michael

No, preventability is the condition of the moral obligation and not actual prevention. It only matters if the action renders the outcome preventable and not actually prevents the outcome (although acting on the obligation should prevent the outcome if it is accurate and a malicious agent is not acting against your efforts, the actual prevention need not be demonstrated for the obligation to hold).

Then what are the necessary and sufficient conditions? — Michael

Those conditions are outlined in the definition and contained in P1:

Gratuitous suffering is suffering that is
1) Known
2) Preventable
with the later addition of
3) At a reasonable cost

Each condition is necessary, but only taken together are the three conditions sufficient for gratuitous suffering.

Then if it can be shown that I can't prevent gratuitous suffering by adopting a vegan diet then I am not obligated to adopt a vegan diet. — Michael

More or less, but you should be careful with what you mean. I would state it as, "gratuitous suffering caused by food production practices is not preventable if it is possible to adopt a vegan diet". The obligation only holds if the means (i.e., a vegan diet) is suitable or renders the outcome (i.e., gratuitous suffering caused by food production practices) preventable. If multiple actions render the outcome preventable, there is no strict obligation to act on any specific action. Veganism is obligated because it is only means to render the outcome preventable (as per P6).

So, if I adopt a vegan diet will gratuitous suffering be prevented? — Michael

Perhaps. There are complex chains that will be played out by your adoption of veganism that may (or by some chance may not) prevent gratuitous suffering. The specifics of how much, where or the mechanisms of prevention are beyond the scope of this argument.

No, preventability is the condition of the moral obligation and not actual prevention. It only matters if the action renders the outcome preventable and not actually prevents the outcome (although acting on the obligation should prevent the outcome if it is accurate and a malicious agent is not acting against your efforts, the actual prevention need not be demonstrated for the obligation to hold).

...

More or less, but you should be careful with what you mean. I would state it as, "gratuitous suffering caused by food production practices is not preventable if it is possible to adopt a vegan diet". The obligation only holds if the means (i.e., a vegan diet) is suitable or renders the outcome (i.e., gratuitous suffering caused by food production practices) preventable. If multiple actions render the outcome preventable, there is no strict obligation to act on any specific action. Veganism is obligated because it is only means to render the outcome preventable (as per P6). — Soylent

As I said before, this doesn't work:

One ought prevent X
X is preventable iff Y is possible
Therefore one ought do Y.

The conclusion doesn't follow. Premise 2 must be "X is prevented iff one does Y" if the argument is to work.

Therefore P9 fails if it's supposed to be defended as a syllogism.

And if it's not supposed to be defended as a syllogism then some other reasoning or evidence is required to defend the material implication. So what do you have to defend the premise that if "one ought prevent gratuitous suffering" is true and if "gratuitous suffering is preventable iff it is possible to adopt a vegan diet" is true then "one ought adopt a vegan diet" is true?

It only matters if the action renders the outcome preventable and not actually prevents the outcome

So the first premise is "one ought do that which makes gratuitous suffering preventable" rather than "one ought do that which prevents gratuitous suffering"?

Veganism is obligated because it is only means to render the outcome preventable (as per P6)

But that's not P6. P6 says "gratuitous suffering is preventable iff it is possible to adopt a vegan diet". It doesn't say "gratuitous suffering is preventable iff a vegan diet is adopted".

So if we're only obligated to make gratuitous suffering preventable then we're only obligated to make the adoption of a vegan diet possible.

It's in the form "if X and Y then Z". I'm questioning this material implication. If the material implication fails then the premise fails, and if the premise fails then the argument fails. — Michael

I'm glad you left the premise in a formal notation because formally it is valid. I have shown X and Y in the argument and I am trying to arrive at Z so the material implication holds by modus ponens. I take your objection to be directed at the content of the terms, and that is supported by an ancillary meta-ethical argument about the entailment of obligations.

it is wrong to allow said gratuitous suffering — Soylent

Can be read in deontic logic as ¬Pγ (It is not permitted to γ)
¬Pγ is equivalent to O¬γ (One is obligated to not γ)

If ¬Pγ and (¬γ iff ψ), then Oψ
¬Pγ and (¬γ iff ψ)

Oψ

I'm glad you left the premise in a formal notation because formally it is valid. I have shown X and Y in the argument and I am trying to arrive at Z so the material implication holds by modus ponens. — Soylent

No it's not.

P1: X
P2: Y
C1: Z

It's not modus ponens. The premise "If X and Y then Z" can't be defended as a valid syllogism.

One ought prevent X
X is preventable iff Y is possible
Therefore one ought do Y. — Michael

This is not my argument though, the first premise is too strong since "One ought to prevent X" is beyond the potency of finite beings. Ought implies can, such that one ought act in such a way that X is preventable by their actions. I cannot be held responsible for the outcome if it is beyond my potency so my responsibility is to my action (i.e., acting so as to render X preventable). *my Kant is showing*

No it's not.

P1: X
P2: Y
C1: Z

It's not modus ponens. The premise "If X and Y then Z" can't be defended as a valid syllogism. — Michael

That's not the argument, the argument is:

P1 If X and Y, then Z
P2 X and Y
C Z

That's not the argument, the argument is:

P1 If X and Y, then Z — Soylent

And I'm asking you to defend P1 (which in the original is P9). What reasoning or evidence shows that X and Y implies Z?

This is not my argument though, the first premise is too strong since "One ought to prevent X" is beyond the potency of finite beings. Ought implies can, such that one ought act in such a way that X is preventable by their actions. I cannot be held responsible for the outcome if it is beyond my potency so my responsibility is to my action (i.e., acting so as to render X preventable). *my Kant is showing*

Then the argument is:

One ought make X preventable
X is preventable iff Y is possible
Therefore one ought do Y.

Again, it's invalid. The conclusion would be "one ought make Y possible" (i.e. "one ought make the adoption of a vegan diet possible").

If you want the conclusion to be "one ought do Y" (i.e. "one ought adopt a vegan diet") then the argument must be:

One ought make X preventable
X is preventable iff one does Y
Therefore one ought do Y

One ought make gratuitous suffering preventable
Gratuitous suffering is preventable iff one adopts a vegan diet
Therefore one ought adopt a vegan diet

Is this what you're arguing?

And I'm asking you to defend P1. What reasoning or evidence shows that X and Y implies Z? — Michael

As per my post above, I think this is what you're after or am I missing the meaning of your request?

it is wrong to allow said gratuitous suffering

Can be read in deontic logic as ¬Pγ (It is not permitted to γ)
¬Pγ is equivalent to O¬γ (One is obligated to not γ)

If ¬Pγ and (¬γ iff ψ), then Oψ
¬Pγ and (¬γ iff ψ)

Oψ

Then is the argument:

One ought make X preventable
X is preventable iff Y is possible
Therefore one ought do Y. — Michael

That's not a charitable reading. The second premise can be stated as X is preventable iff Y (where Y is "it is possible to adopt a vegan diet"). There's no reason to place the possibility outside Y. It is possible that the amendment of Y as suggested by Postmodern Beatnik has changed the conclusion and I haven't properly adopted the premise throughout. It's a remnant of an older version of the argument, but you're quite right to bring it to my attention as being out of place in the current form.

I'll review the argument to see if it is salvageable in light of your criticism or if the amendment has weakened the argument beyond repair.

The second premise can be stated as X is preventable iff Y (where Y is "it is possible to adopt a vegan diet") — Soylent

Sure. But then the conclusion is "one ought make it possible to adopt a vegan diet". If the conclusion is supposed to be "one ought adopt a vegan diet" then the second premise must be "Gratuitous suffering is made preventable iff one adopts a vegan diet".

You can't have Y as "it is possible to adopt a vegan diet" in the premise and then have Y as "adopt a vegan diet" in the conclusion.

You can't have Y as "it is possible to adopt a vegan diet" in the premise and then have Y as "adopt a vegan diet" in the conclusion. — Michael

I'm curious if there is a move to be made from Y¹ to Y, where Y¹ is "it is possible to adopt a vegan diet" and Y is "to adopt a vegan diet". Perhaps another ancillary argument of the nature of "if it is possible to Y (Y¹) then one ought to Y iff Y is the only means to Z and one ought to Z".

"if it is possible to Y then one ought to Y iff Y is the only means to Z and one ought to Z" — Soylent

That works. But what's Z? "Make gratuitous suffering preventable"? Then "Y is the only means to Z" is "adopting a vegan diet is the only means to make gratuitous suffering preventable", which is the revised premise I offered: "gratuitous suffering is preventable iff a vegan diet is adopted".

I'll review the argument to see if it is salvageable in light of your criticism or if the amendment has weakened the argument beyond repair. — Soylent

It seems Postmodern Beatnik is more keen than I am, anticipated this problem and performed the heavy lifting here.

P9 still suffers from the same problem. The consequent isn't deducible from the antecedent. Therefore the material implication must be defended on other grounds.

N.b I am new to this discussion. I have not read the other discussion to which you refer, nor, at this time, have I read any other comments in this discussion.

The argument seems valid, so I'll address the issue of soundness.

P1 If any gratuitous suffering is preventable and known, then it is wrong to allow said gratuitous suffering. — Soylent

False. It's not true at any cost. If the cost of prevention is too great, or even if the risk is too great, then it's not necessarily wrong.

P6 Gratuitous suffering caused by food production practices is preventable if and only if it is possible to adopt a vegan diet.* — Soylent

False. There are possible means of prevention which do not require the possibility of adopting a vegan diet. For example, some such suffering would be prevented if the level of production was reduced, and all such suffering would be prevented subsequent to the cessation of all non-human sentient life.

Therefore, the argument, in it's present form, is unsound.

By the way, I noticed the asterisks at the end of certain premises, but I haven't seen any corresponding notes.

Edit:

I think part of your objection is covered by my reasonable cost condition not yet mentioned here. — Soylent

Why didn't you include that explicitly in the argument in the first place? If your objective here is not to put an argument in what you know to be it's best formulation to scrutiny, but just some sort of test of our critical thinking skills, then I don't agree with your purpose here, and wish to take no further part. I don't feel like playing a game of 'spot the shortcomings in my knowingly inadequate argument'.

I'm going to offer a revised argument taking into consideration the discussion thus far. I would like to thank everyone that has contributed for their thoughtfulness and civility.

Stipulative Definitions:
Veganism is any diet that does not include sentient animals as the end product in food production practices. Veganism is qualified by the omission of food products In a diet and as such is an act of omission.

Gratuitous suffering is morally impermissible suffering. The necessary and sufficient conditions of morally impermissible suffering is any suffering that is: known, preventable, and preventable at a reasonable cost.

P1 If any gratuitous suffering is preventable and known and the means to make the gratuitous suffering preventable are reasonable, then it is wrong to allow said gratuitous suffering. (from stipulative definition)
P2 If some nonhuman animals are sentient and food production practices would constitute gratuitous suffering in humans, then food production practices constitute gratuitous suffering in some nonhuman animals.
P3 Some nonhuman animals are sentient.
P4 Food production practices would constitute gratuitous suffering in humans.
C1 Food production practices constitute gratuitous suffering in some nonhuman animals. (from P2, P3 and P4)
P5 If food production practices constitute gratuitous suffering in some nonhuman animals, then some agents know of some gratuitous suffering.
C2 Some agents know of some gratuitous suffering. (from C1 and P5)
P6 Gratuitous suffering caused by food production practices is preventable if and only if it is possible for some agents to adopt a vegan diet.
P7 If it is possible for some agents to adopt a vegan diet, then gratuitous suffering caused by food production practices is preventable. (elimination from P6)
P8 It is possible for some agents to adopt a vegan diet.
C3 Gratuitous suffering caused by food production practices is preventable. (from P6, P7 and P8)
P9 If the means of making the gratuitous suffering caused by food production practices preventable is an act of omission and does not present harm to some agents, then the means to make said gratuitous suffering preventable is reasonable.
P10 Adopting a vegan diet is an act of omission (from stipulative definition)
P11 If some agents do not have health concerns (mental or physical) that can only be remedied by adopting a non-vegan diet, then a vegan diet does not present harm to some agents.
P12 Some agents do not have health concerns (mental or physical) that can only be remedied by adopting a non-vegan diet (*edited January 6, 2016 @ 13:06 est by adding P12 and renumbering subsequent premises)
C4 A vegan diet does not present harm to some agents. (from P11 and P12)
C5 The means to make said gratuitous suffering preventable is reasonable. (from P9, P10, and C4)
C6 It is wrong to allow gratuitous suffering caused by food production practices. (from P1, C2, C3, and C4)
P13 If some agents belong to the sets of "some agents" contained in each of C2, P8, and C4 respectively, then there are those agents who are in a position to adopt a vegan diet.
P14 Some agents belong to the sets of "some agents" contained in each of C2, P8, and C4 respectively.
C7 There are those agents who are in a position to adopt a vegan diet. (*edited January 6, 2016 @ 10:21 am est* from P13 and P14)
P15 If it is wrong to allow gratuitous suffering caused by food production practices and gratuitous suffering caused by food production practices is preventable if and only if it is possible to adopt a vegan diet, and there are those who are in a position to adopt a vegan diet, then a vegan diet ought to be adopted by all those who are in a position to adopt a vegan diet.
C8 A vegan diet ought to be adopted by all those who are in a position to adopt a vegan diet (from P6, C6, C7 and P15).

This was written on my phone and may contain typographical errors or omission. The above is subject to revision once I have access to a desktop computer to correct obvious errors. I will mark edits as such including a time stamp.