There was a time when an animal could be put on trial for murder. Nowadays, that might seem unheard of in New York due to the modern understanding of what defines murder and who can be held morally responsible for the action.
Animals can’t be murderers
In order to change the policy around trying animals for murder, the entire legal process surrounding the definition of these legal terms had to evolve as well. The belief that an animal couldn’t possibly understand enough about morality to commit murder is still the prevailing consensus nowadays. Once it was decided and agreed upon that an animal couldn’t possibly have an understanding of the morality behind its actions, the way was paved for questioning whether all humans have this understanding.
This question of mental compacity for moral reasoning became central to the conversation. With animals, it’s an expectation that they’re operating on a different level. They may have a basic understanding of good and bad outcomes but don’t have a worldview of what is right and wrong morally. It’s simply because this isn’t what animals evolved to do. In fact, it’s contrary to the lifestyle they’ve adapted to for their survival.
How this applies to people
The same no longer applies to humans, of course. The insanity plea highlights the difference someone between breaking the law willfully or because they can’t tell the difference between right and wrong.
With a plea of insanity, the question isn’t whether or not a person decided to act morally right. Instead, the law focuses on a person’s ability to distinguish between right and wrong. For instance, someone who knows what they’re doing is wrong but makes excuses for themself isn’t experiencing issues with their moral reasoning. They would therefore still be found guilty.
When someone is found not guilty after pleading insanity, the individual isn’t usually just allowed to go free. Often, they will be placed in an environment where they can be supervised and receive the treatment they need.
Besides the lack of agreement over what is morally right or wrong in the first place, people don’t always agree on whether an accused individual had the capacity for morality. With an insanity plea, it is possible to be found not guilty for crimes that were committed by someone who doesn’t have the ability to understand what moral decisions are.