Moral judgment about a given case requires consistency in taste such that, it can apply to other related matters. It calls for a willingness to judge a situation from more than one viewpoint to achieve consistency in judgment and avoid subjective judgment (Weston 245).
For instance, a pro-life proponent arguing that abortion is an act of killing should also oppose the death penalty because it is also an act of killing. In order, to achieve consistency in judgment, the cases compared must have a morally relevant similarity.
Otherwise, one can argue that the cases are not similar and therefore should not be judged alike or decide to change the judgment about the first case to suit the second case.
Invented cases provide a moral imagination that is effective in achieving a morally consistent judgment. Judith Thomson invented case; the right to life and the unconscious violinist offers a logical explanation that is important in addressing the problem of inconsistency.
This imaginary case seeks to involve men to imagine of an unintentional pregnancy and thus make a consistent judgment.
However, one can argue that the two cases are different as pregnancy is intentional while attachment to an unconscious violinist is unintentional affair and as such be judged differently.
Colin McGinn uses two analogies to give a moral explanation of the human treatment of other animals termed ‘speciesism’ (Weston 254). In his first analogy, McGinn tells of a particular vampire species that rely on human blood and orange juice for their diet.
The vampires even rear human infants for the sole purpose of replenishing their stock of blood, and they do not see their actions as morally wrong as they consider humans different and inferior to them. However, amongst the vampires are proponents of humane treatment of humans.
They also advocate for change of diet from reliance on human blood to orange juice. The others who are the majority and prefer human blood as their main diet often ignore the proponents.
The vampires, in this case, are analogous to humans who mistreat other animals because they are biologically different from humans. Also, animals are considered to intellectually inferior to humans.
Humans justify the exploitative treatment of animals because they are biologically different and have limited cognitive abilities. However, the analogy removes the ‘speciesist’ bias since humans would oppose the mistreatment of humans by other animals the way humans do.
The second analogy addresses the human assumption of mental inferiority of animals as compared to humans. Colin tells of two humanlike species that are very much alike, and they even have similar intellectual capabilities.
However, one of these species ‘the human’ cannot defend itself from the other species, the human. As a result, the human species exploits the ‘shuman’ species without considering it morally wrong.
This analogy removes intelligence bias as a moral justification for the exploitative treatment of animals.
Colin further proposes that the exploitation of animals because of their intellectual inferiority justifies the same treatment to simple humans, aged people, or retarded adults whose intellectual development is limited.
Colin also talks of the inappropriateness of slavery and child labor that were historically morally justifiable. However, at present, this is viewed as barbaric acts that have no moral ground. The two analogies remove species and intellectual differences as a basis for moral justification.
Colin concludes that intellectual superiority or species differences between animals and humans do not provide any moral justification of the human exploitative treatment of other animals.
Weston, Antony. A 21st Century Ethical Toolbox. New York: Oxford University Press, 2000: 245-257