To understand why this debate matters, one must look at specific arenas where the two philosophies produce radically different outcomes.
The more we learn about animal cognition, the harder it is to justify the lab cage or the gestation crate. If a pig can suffer from PTSD, how can we justify confining it? The welfare response is to give the pig a toy. The rights response is to let the pig go. To understand why this debate matters, one must