The Antispeciesist Revolution
When is it ethically acceptable to harm another sentient being? On some fairly modest assumptions, to harm or kill someone simply on the grounds they belong to a different gender, sexual orientation or ethnic group is unjustified. Such distinctions are real but ethically irrelevant. On the other hand, species membership is normally reckoned an ethically relevant criterion. Fundamental to our conceptual scheme is the pre-Darwinian distinction between “humans” and “animals”.
In law, nonhuman animals share with inanimate objects the status of property. As property, nonhuman animals can be bought, sold, killed or otherwise harmed as humans see fit. In consequence, humans treat nonhuman animals in ways that would earn a life-time prison sentence without parole if our victims were human. From an evolutionary perspective, this contrast in status isn’t surprising. In our ancestral environment of adaptation, the capacity to hunt, kill and exploit sentient beings of other species was fitness-enhancing(2). Our moral intuitions have been shaped accordingly. Yet can we ethically justify such behaviour today?
Naively, one reason for disregarding the interests of nonhumans is the dimmer-switch model of consciousness. Humans matter more than nonhuman animals because (most) humans are more intelligent. Intuitively, more intelligent beings are more conscious than less intelligent beings; consciousness is the touchstone of moral status.
The problem with the dimmer-switch model is that it’s empirically unsupported among vertebrates with central nervous systems, and probably in cephalopods such as the octopus as well. Microelectrode studies of the brains of awake human subjects suggest that the most intense forms of experience, for example agony, terror and orgasmic bliss, are mediated by the limbic system, not the prefrontal cortex. Our core emotions are evolutionarily ancient and strongly conserved. Humans share the anatomical and molecular substrates of our core emotions with the nonhuman animals whom we factory-farm and kill. By contrast, distinctively human cognitive capacities such as generative syntax, or the ability to do higher mathematics, are either phenomenologically subtle or impenetrable to introspection. To be sure, genetic and epigenetic differences exist between, say, a pig and a human being that explain our adult behavioural differences, e.g. the allele of the FOXP2(1) gene implicated in the human capacity for recursive syntax. Such mutations have little to do with raw sentience(1). (via The Antispeciesist Revolution)