Contemporary botany has witnessed an upheaval in its understanding of the electrophysiology, cell biology and signalling systems of plants. An insurgent school of botanists have coined the phrase plant neurobiology to describe a new field that is “aimed at understanding how plants perceive their circumstances and respond to environmental input in an integrated fashion.” Neurobiologists credit plants not only with powers of perception but also intelligence, learning and memory. Although controversial and disputed within botany, neurobiologists have inspired some moral philosophers to argue for a revised view of the moral status of plants. By questioning the chasm of moral inferiority that has long been thought to separate plants from animals, philosophers inspired by plant neurobiology are predictably viewed as providing a justification for meat-eating. Plant neurobiology is effective in showing that the traditional image of plants as “inert, vacant, raw materials” is outdated. But challenging protectionism’s ban on eating animals requires showing that plants possess equal moral status to animals. It also needs to be shown that in a world of sentient plants, the diet that would harm the fewest sentient beings is some form of omnivorism. The plant thinking view fails to establish either claim.

A popular view holds that no wrong is done to an animal when it is killed painlessly. In arguing against this view in the previous chapter, I granted for the sake of argument that chickens are merely sentient. I framed the discussion this way to make clear that the case against anti-speciesist versions of humane slaughter does not depend on revisionary claims about the cognitive abilities of food animals. Contemporary science, however, suggests that the cognitive abilities of chickens are more extensive than is generally recognized, to the point that they possess a primitive form of self-consciousness. If chickens have mental abilities that place them in an intermediate status between merely sentient beings and persons, this will have bearing not only on the arguments I examined in the last chapter, but on any attempt to justify slaughtering them, including attempts that employ Singer’s or potentially other versions of protectionist theory. The revised understanding of chicken cognition thus poses a separate challenge to protectionist arguments for humane slaughter, independent of the challenge posed by the time-relative interest account. The version of primitive self-consciousness that I defend innovates on previous versions to include a primitive ability to conceive of oneself through time.

This chapter analyzes the ethics of killing animals when animals are assumed to be unable to form desires about the future and to lack a conception of themselves through time. Even if their mental abilities are so limited, they can still be harmed by being killed, and so inducing their deaths will require justification. My argument employs the notion of a time-relative interest, which is the interest an entity has in continuing to live. This interest is shaped by two factors: the gain or loss of future well-being, and the amount of psychological continuity between the entity now and in the future (when its well-being improves or declines). After outlining the time-relative interest account I note how it differs from another influential argument that takes future well-being into account, Don Marquis’ argument against abortion. I then defend the time-relative interest account from the criticism that it fails to grant weight to interests a deceased individual would have come to posses had he or she not died. Finally, I show why my view is consistent with a universal legal ban on infanticide.

Animal rights and related notions of animal protection have long been thought to entail a plant-based diet. An increasingly popular view in the animal ethics debate challenges this idea by arguing that even if animals warrant a high degree of moral standing we are permitted or even obliged to eat meat. Some arguments to this effect maintain that greater harms accrue to animal in plant agriculture than in certain forms of free-range animal husbandry. Others cite a loss in value that would occur if animals raised for food no longer existed. Still other arguments for ethical omnivorism cite new technologies such as humane slaughter systems, which are said to painlessly kill animals in a manner consistent with Peter Singer's philosophy of animal liberation, or in vitro meat, which is sourced in a petri dish rather than the body of a living animal. Finally some philosophers invoke plant "neurobiology" to challenge the possibility of not eating sentient beings. Despite their differences these arguments all defend a new omnivorism, one that justifies eating meat within a framework of animal protection.

The rise of humane slaughter and Peter Singer’s support for it have given rise to the view that Singer’s philosophy of animal liberation, rather than requiring veganism, entails only avoiding factory farmed meat. Proponents of this view cite passages in Singer’s work that suggest killing animals can be permissible when it is done painlessly, among other conditions. This reading of Singer raises the possibility that it is possible to endorse anti-speciesism and the equal consideration of interests and continue to eat animals. In evaluating this claim, I examine humane slaughter as it is actually practiced on chickens. I also examine a hypothetical ideal version that eliminates all suffering from the slaughter process. In doing so I distinguish two versions of Singer’s argument for animal liberation, one based on utilitarianism and the other on equal consideration, and argue that regardless of what version of humane slaughter we have in mind, actual or ideal, neither is justified by either of Singer’s arguments. The support Singer has offered for humane slaughter is therefore amore accurately viewed as a pragmatic effort to reduce the suffering of food animals rather than the outcome of applying Singer’s theory at an ideal level.

In 2013 researchers at a lab in the Netherlands created a hamburger by taking stem cells from a piece of beef and exposing it to a growth hormone to induce growth. The result was a new kind of hamburger: one made from beef, but which was not carved out of the body of an animal. In vitro meat is flesh that was not derived from the carcass of an animal. As such, it redeploys a concept familiar to protectionism, that of meat itself, so as to finally justify a new omnivorism. In vitro meat represents a form of meat-eating that protectionism should condone, even celebrate. Its arrival should prompt us to widen our concept of what meat is to include lab-grown beef, pork, and chicken. It should also oblige us to examine the criticisms of in vitro meat that have been made by thoughtful animal protection philosophers, and show how such criticisms can be overcome. Crucial to doing so is revising our concept of what meat is.

The philosophy of animal protection traditionally takes for granted our least controversial moral views, such as the idea that other human beings can make genuine moral claims on us. It then seeks to enhance them with further principles of its own. In this way it is like an application for a phone or computer, which achieves functionality by being added to an existing operating system. My primary concern is with the operating system, not the application. I seek to outline two principles that have been common to most versions of animal protection: anti-speciesism and moral individualism. While not every argument for protectionism endorses both claims, the great majority do, and so outlining these two principles are the best place to begin. (Insofar as a critique of protection rejects either of these notions it will be a rejectionist critique rather than a separatist one.) Both principles achieve their force by presupposing certain moral claims that are not unique to protectionism. The most relevant of these are the bedrock claim that causing human suffering requires justification, and that moral judgment commonly (but not universally) involves extending equal consideration to the interests of individuals affected by our decisions.

Steven Davis has offered an influential argument for the view that the diet most consistent with animal protection philosophy is one that contains some meat. Davis cites the accidental death of field animals during vegetable harvesting. Empirical studies suggest that the number of field mice, rats, and similar creatures killed in crop cultivation may outnumber the total animal deaths involved in the raising of beef cattle, so long as the cows are raised on a diet of grass rather than grain. If so, then the most logical diet for animal advocates to adopt is one that includes hamburger and milk from grass-fed cows, in order to reduce the overall number of animals killed. Davis's argument for burger veganism overlooks philosophically significant forms of harm to human beings that are present in beef production but not vegetable harvesting, and bases his argument on the implausible assumption that there is no difference between deliberate and accidental killing. A final problem bedevils not only Davis’s orginal argument but subsequent variations that defend eating Australian red meat and roadkill. It is that more than one current trend in plant agriculture causes little or no collateral harm to animals.