And if you think about claims about the nonexistence of things, one obvious way to try and establish the nonexistence of a purported thing would be to offer a definition of that thing and then to see whether anything satisfied it.
如果你想想 其他的不存在的事物， 一个很明显的检验这个观点 是不是不存在的一个方法是 按照这些观点定义这个事物， 然后看看是否能寻找到符合这个定义的事物。