> The only reason why animal consciousness has been controversial historically is a religious one
In your sentence I would substitute ''religious'' with other more specific terms like ''Judeo-Christian'' since Jainism and Hinduism have been talking about a continuum of consciousness in all living things for almost 3,000 years: specifically described by them as the Ātman and the Jiva.
In your sentence I would substitute ''religious'' with other more specific terms like ''Judeo-Christian'' since Jainism and Hinduism have been talking about a continuum of consciousness in all living things for almost 3,000 years: specifically described by them as the Ātman and the Jiva.
https://en.wikipedia.org/wiki/%C4%80tman_(Hinduism)
https://en.wikipedia.org/wiki/Jiva