They are some of the best-known adverts in television history. Families of chimpanzees in human clothes, riding bicycles, pouring tea and even driving cars. They were made to advertise PG Tips, the most popular brand of tea in Britain. But were they exploiting the animal actors?

Nowadays, tastes have changed and the adverts look old-fashioned. In fact, the Spanish government is considering a law that would completely ban the use of chimps for commercial purposes, including circuses, shows and advertising.

It is not just chimps that Spain wants to protect. The law relates to the entire great apeThe Hominidae or Hominid family of primates, including orangutans, gorillas, chimpanzees, bonobos and humans. family of primates, which includes gorillas, orangutans and bonobos. As well as commercial use, the law would ban scientific testing if it causes harm.¹

At present, 29 countries around the world have passed laws protecting great apes from harmful research.² But the law in Spain goes beyond experiments, arguing great apes have cognitiveRelating to the processes of thinking and reasoning. abilities that "bring them close to those of human beings".³

Peter Singer, the respected philosopher, is one of many academics who support the proposal. He praised the Spanish government for respecting the "dignity" of these animals.⁴

Others have concerns. Many animals have some cognitive ability, but are still used in scientific research, or else farmed for meat and other products. Why should great apes be given "dignity," but not horses, cows, or dogs?

At the centre of this debate is the concept of personhood. These are the qualities that make people distinct from animals and deserving of human rights, protections and privileges.

Many philosophers argue that humans have a unique capacity for self-awareness, empathyThe capacity to understand and feel the suffering of others. and the ability to understand complex rules or think abstractly. But there are humans who do not share these abilities - like people with learning difficulties - who still count as persons.

In recent years, some scientists have argued that personhood should be applied to great apes, and some lawyers have argued that personhood should be applied to all animals.⁵ There are even environmental activists who believe ecosystemsComplex networks of living things that rely on each other to survive. like forests or rivers could qualify. Sure enough, if Spain passes this law, the idea of personhood will only grow bigger.

Is this morally right?

Yes: Humans and great apes share a common ancestorA person related to us who lived a long time ago. and similar levels of cognitive ability. Therefore, they should be given the same rights and protections that people enjoy.

No: If cognitive ability means an animal should be treated like a human, we cannot simply protect great apes. Farming animals for food, dairy, or leather will also have to be stopped.

Or... It can be hard to draw a clear dividing line between humans and animals. But, if we do not draw a line somewhere, the concept of personhood becomes meaningless.