It's true that moral arguments are not like mathematics where an answer can be proven beyond doubt. However, we can use logical arguments to try to convince someone that something is right or wrong. We can also draw upon people's current moral framework and highlight inconsistencies in the way they behave. The vast majority of people do not condone unnecessary cruelty and death of animals. I believe that most people already have a vegan moral framework that they don't actualize because it's inconvenient. We only have to look at the way people fetishize particular animals over others, like pets. I find it bizarre to watch animal rescue TV shows were extensive resources are used to retrieve a stray kitten from a drain, yet people are comfortable with billions of animals being slaughtered every year. Our treatment of animals is inconsistent and completely illogical. Much like the human rights movement, it was the inconsistency in the way that people were treated i.e. slavery, due to the colour of their skin. Hundreds of years ago there was no shortage of people who would try to convince you that slavery was not immoral. But the people who fought for the abolition of slavery weren't morally superior or somehow infallible, perfect or Christ-like. This didn’t matter at the time and doesn’t now. For example, a person argues that domestic violence is wrong, yet later the same person is found to have embezzled large sums of money. Does this mean that everything the person said is wrong and that domestic violence is in fact okay? Of course not. Now obviously I have a much better chance of convincing someone of my argument if I adhere to it, but in the end it doesn't matter. I may convince you that it is important to care for the environment but whether I recycle or not, it doesn’t change the fact that we should care for the environment.
Morals are always evolving and it’s only by reflecting upon our society, our behaviours and our beliefs can we move forward. Throughout history shifts towards greater equality and the reduction of cruelty have always begun with the few.
