The term speciesism was coined by psychologist Richard Ryder in 1975:

“I use the word ‘speciesism’ to describe the widespread discrimination that is practised by man against other species … Speciesism is discrimination, and like all discrimination it overlooks or underestimates the similarities between the discriminator and those discriminated against.”

Since then, others have proposed their own definitions of speciesism. Most of these were critiqued by Joan Dunayer in her book, Speciesism. She offers the following definition:

“A failure, in attitude or or practice, to accord any nonhuman being equal consideration and respect.”

There are (at least) three ways of looking at speciesism:

Psychological: individually held prejudice

Prejudice is a primarily a psychological term. It refers to an individual’s belief and can provide a justification for discriminating against others. There was a time when racism was considered primarily a psychological disorder, but now racism and other “isms” like sexism, heterosexism and speciesism are more often viewed in a wider social context.

Philosophical: discrimination

Moral philosophy considers the morality of actions and looks at speciesism in terms of whether or not speciesist actions (discrimination) are justified. The determination that speciesism is unjustified would be true whether there were prejudice involved or not.

The definitions used by philosophers are most often based on Richard Ryder’s view of speciesism, narrowly defined to include only discrimination based on species membership alone. Moral philosopher Oscar Horta defends the following broader definition, which includes any discrimination against nonhuman animals, whether the discrimination is based on species membership or not.

“Speciesism is the unjustified disadvantageous consideration or treatment of those who are not classified as belonging to one or more particular species.”

Note: “unjustified disadvantageous consideration or treatment” is just a more technical way of saying discrimination.

Sociological: shared ideology

Currently the “isms” including racism, sexism, heterosexism and speciesism are most often viewed as social problems and are looked at from a sociological perspective, which sees them as shared belief systems that give rise to and reinforce prejudices and legitimate discrimination. Sociologist David Nibert explains:

“An ideology is a set of socially shared beliefs that legitimates an existing or desired social order.”

Sociologists no longer look for the causes of oppression in individual beliefs, attitudes and actions. They tend to view prejudice (an individual attitude) and discrimination (such as mistreatment) as outgrowths of oppressive ideologies. They support and perpetuate the ideologies, but do not cause them. Sociologists stress the social structural and economic nature of oppression. They examine the unequal relationships and institutional and organizational discrimination that emerge as a result.

Though the sociological view gives the fullest picture, these three approaches to understanding speciesism are complementary.