Variation on the Argument from Marginal Cases

I have recently thought of a puzzling, but potentially revolutionary variation on the Argument from Marginal Cases. I am not exactly at the stage where I can conclusively say that this variation establishes its conclusion, but it has given me great pause.

The standard form of the Argument from Marginal Cases is well known. It runs as follows:

PREMISE 1: Assume that some trait T, such as intelligence, moral agency, the ability to appreciate art, the ability to feel romantic attachment, etc, is the sole determiner of moral status.

PREMISE 2: Some humans as a matter of fact do not possess the aforementioned trait.

CONCLUSION 1: Some humans (i.e. marginal cases) do not have moral status.

PREMISE 3: But, the aforementioned marginal humans actually do have moral status.

PREMISE 4: If the aforementioned marginal humans do have moral status, then trait T is not the sole determiner of moral status.

CONCLUSION 2: Trait T is not the sole determiner of moral status.

The obvious intention of this argument is to demonstrate that many proposed determiners for moral status are insufficient, because there will always be some humans who we intuitively believe to possess moral status who will be classified as not possessing such status as a result of applying this argument.

But, as people who follow debates on Animal Rights are all too aware, those who propound this argument do generally agree that there is in fact a sole determiner for moral status that is not susceptible to the argument. The criteria, of course, is that of sentience. Sentience, i.e. the ability to have subjective experience, is said to be the key that unlocks the gateway to moral status.


The usage of this argument, and the eventual appeal to sentience as the criteria,  usually leaves the opponent with one of two options:

1. He can define moral status as being determined solely on the basis of species membership.

2. He can accept the conclusion of the argument and follow the Vegan lifestyle.

Option 1 is obviously recalcitrant, since it is just an example of speciesism, and thus embodies the same sorts of prejudices as racism, sexism, ageism, classism, etc.

Option 2, though indeed the sensible conclusion, is also considered recalcitrant because of the personal sacrifices that the Carnist must make.


This is all standard fare to those deep among the milieu of animal philosophy. But what I want to bring under consideration is the notion of sentience as the criteria for moral status. For, as should be clear enough, not all humans are sentient.

Quite apart from such trivial cases as dead and not-yet-born humans, there are real instances of living humans that lack the property of sentience. The most obvious example is people who are comatose, but certain severe and profoundly disabled humans might also  lack sentience. But there is a universal instance where living humans lack sentience, namely, when they are asleep. We will refer to all humans who fall under these instances as "Non-S Humans."

Let us test this criteria by formulating a new version of the Argument from Marginal Cases with it in mind. We might formulate it as follows:

PREMISE 1: Assume that sentience is the criteria for the possession of moral status.

PREMISE 2: Non-S Humans do not possess sentience.

CONCLUSION 1: Non-S Humans do not possess moral status.

PREMISE 3: If Non-S Humans do not possess moral status, then it is morally permissible to treat Non-S Humans in any way we please (for instance, to rape them).

PREMISE 3: But it is not morally permissible to treat Non-S Humans in any way we please.

CONCLUSION 2: Non-S Humans do possess moral status.

PREMISE 5: If Non-S Humans do possess moral status, then sentience is not the criteria for the possession of moral status.

CONCLUSION 6: Sentience is not the criteria for the possession of moral status.


As we can see, this argument operates essentially on the same sort of principle as the standard AMC. We propose a criteria for moral status, but then we note that this criteria does not apply to all humans, and that the humans it does not apply to do seem to really possess moral status.

But just why is this argument so revolutionary? Well, if it is correct, then it would at the very least strongly point us to the notion that all living things have moral status merely by virtue of the fact that they are living. This fact in turn, would imply that the typical sentiocentrist ethic of the Vegan movement is radically mistaken, and that we Vegans need to move toward a biocentric or an ecocentric ethic.

In addition, this would also seem to have implications for the question of abortion. For some fetuses, especially early term fetuses, appear to lack the property of sentience

Now the we have laid the argument out and hinted at some of its possible implications, let us think of how we might respond to it. There is one obvious objection, and that concerns those Non-S Humans who are normal humans that are just currently asleep. In this case, the objection would be that the Non-S Human in question has an Aristotelian potentiality of sentience, in much the same way that a person with their eyes closed has an Aristotelian potentiality for seeing.

So far as I have been able to tell, this objection seems plausible. But we must note that it is not so easy when it comes to the other sorts of Non-S Humans, viz. the extreme cases of severe and profoundly disabled people and the comatose. But even in these cases, we can put forth a modified objection. We would say, not that they possess the Aristotelian potentiality for sentience, but that they possess the potentiality simpliciter for sentience, in much the same way as I possess the potentiality simpliciter to read and understand a graduate-level string theory textbook.

However, we still have a defense. We can posit that the Non-S Humans under consideration do not possess the potentiality simpliciter for sentience. This obviously leads us into a consideration of the different types of modality in order to determine just what sort of potentiality is at issue. I don't think that we can say that it is either logically or metaphysically impossible for these Non-S Humans to possess sentience. Physical impossibility is I think much closer to what we need, but I am not prepared to go quite that far. I think what we are after here is biological impossibility. Thus, we can posit that it is biologically impossible for the Non-S Humans to possess sentience, meaning by this that their possessing sentience is not consistent with the facts of human biology.

Now, we might have a hard time conceiving of how this could apply to a extreme severe and profoundly disabled person, so let us just focus on the case of the comatose person. In other words, what we are dealing with is a human that is irreversibly comatose.

So now that we have that in focus, the real question we must consider is: would it be wrong for someone to mistreat this human in anyway they please? For instance, to rape them?

To avoid some possible objections, we will say that the irreversibly comatose human has no friends or family members and that there is no way that anyone could find out that they had been raped.

Now to me, at least on a first approximation, it appears that it would be a profound moral injustice for someone to rape an irreversibly comatose human. But, and here is the catch, it seems to me that doing so would be to directly wrong the comatose human.


This seems to be the central issue on which the entire argument rests. Now of course, someone very well might respond to my intuition by pointing out that raping an irreversibly comatose human cannot be a direct wrong, because there is no center of experience that can be the object of the wrong. In other words, there is no 'person' as such that can be wronged.

Taking this response into consideration, I think that the ultimate conclusion that we draw from this argument will depend on our answer to a further question, namely: Does the existence of value as such necessarily depend upon the existence of a valuer?

The way I would like to approach this question is by an analogy. Let us suppose for the sake of argument that there is an afterlife. Let us also suppose that you had undergone a terrible accident that left you irreversibly comatose. After some time, you pass away and you enter the afterlife state. Upon entering this state, you are informed that some time after you had become comatose, a person had sexually assaulted your body. How would you react to this shocking information? Would you say that you yourself had been morally wronged? Or would you react with indifference, since you were not subjectively harmed in anyway by this event?

From my point of view, I am sure that I would very definitely find that I myself had been morally wronged, and it is my strong suspicion that many other people would agree with me on this. However, I should say though that it is not at all clear to me that non-sentient living beings should be given the same moral consideration as sentient living beings. Perhaps the sentiocentrist is definitely gesturing at an ultimate truth, namely that sentience, though not the only determiner for moral status, definitely places one higher on the totem pole than a merely living item.

Or perhaps the argument presented above is just mistaken and sentience is in fact the sole determiner. If that is the case, I would love to hear your objections to the argument.