Singer and Animals

Singer’s Theory: PEI & SP & IU.

The Principle of Equality of Interests (PEI): All similar interests have equal moral weight.

D1. x has an interest in y =df. y makes a difference to the well-being of x.

The Sentience Principle (SP): A being has interests iff it is sentient (i.e., experiences pleasure or pain).

Interest Utilitarianism (IU): An act is morally right iff it maximizes interest satisfaction.

A set of practices, P, is morally acceptable on an IU standard iff there is no set of practices, P’, such that the enactment of P' would result in greater interest satisfaction for the world than would the enactment of P.

Singer’s argument schema against various current practices concerning animals:

1. Animals are sentient.
2. If (1), then animals have interests. (SP)
3. If animals have interests, then those interests are equal in moral weight to similar human interests. (PEI)
4. If similar animal interests and human interests are equal in moral weight, then [act/practice X] fails to maximize interest satisfaction.
5. If [act/practice X] fails to maximize interest satisfaction, then [act/practice X] is morally wrong. (IU)
6. Therefore, [act/practice X] is morally wrong.

What sorts of acts and practices can be substituted for X here?

What sorts of acts and practices does Peter Singer believe can be substituted for X here in the construction of sound arguments?

A Central Argument in Peter Singer's "Animal Experimentation" and "All Animals are Equal"

1. Either (a) human infants possess no morally relevant characteristic that adult mammals of other species lack or (b) human infants do possess a morally relevant characteristic that adult mammals of other species lack and that characteristic is the potentiality to become more aware of what is happening to them, more self-directing, etc.
2. If (a), then it is morally wrong to experiment on human infants iff it is morally wrong to experiment on adult mammals of other species.
3. If (b), then generally, human abortions are morally wrong.
4. It's not the case that generally, human abortions are morally wrong.
5. Therefore, it is morally wrong to experiment on human infants iff it is morally wrong to experiment on adult mammals of other species.
   

• Rationale for Premise (2): Saying that it is wrong to experiment on human infants but not on an adult mammal of another species is blatant speciesism, unless there is some morally relevant characteristic that the human infant has and the adult mammal lacks.
• Rationale for Premise (3): The potentiality in the human zygote, embryo, and fetus is the same as the potentiality in the human infant.

Perhaps you reject Singer's argument by rejecting the controversial premise (4). Perhaps you believe most abortions to be morally wrong in virtue of some version of the Argument from Potentiality. Notice however that many impaired infants lack the potentiality to become rational in any interesting sense. So consider this version of Singer's argument:

1. Sufficiently impaired human infants possess no morally relevant characteristic that adult mammals of other species lack.
2. If sufficiently impaired human infants possess no morally relevant characteristic that adult mammals of other species lack, then it is morally wrong to experiment on sufficiently impaired human infants iff it is morally wrong to experiment on adult mammals of other species.
3. Therefore, It is morally wrong to experiment on sufficiently impaired human infants iff it is morally wrong to experiment on adult mammals of other species.

Can you think of an objection against any of these premises?