When a new movement in art attains a certain fashion, it is advisable to find out what its advocates are aiming at, for, however farfetched and unreasonable their principles may seem today, it is possible that in years to come they may be regarded as normal.

【参考译文】

 当一场新的艺术运动形成某种时尚时，理应弄清其倡导者的目标所在，因为，无论他们的准则在今天看来是多么牵强附会、不可思议，将来都有可能被视为是正常的。

【参考解析】

However这里引导的是一个让步状语从句。其基本结构是：However + 形容词/ 副词 + 主语 + 谓语 （即一个完整的主谓结构）

【更多例句】

1.However fast he runs,he can’t catch up with us. 不管跑多快他都赶不上我们。

2. However hungry I am, I never seem to be able to finish off this loaf bread.无论多饿，我好象永远也吃不完这块面包似的。