Barring extreme circumstances, most of these are just alibis. 除去极端的环境不说，很多这些假设不过是借口。
This hypothesis remains contentious because it assumes the existence of highly unstable conditions, which may not be attainable. 这项假说仍有争议，因为它假设必须有非常不稳定的条件存在，而自然环境可能无法满足这种极端条件。
