The world is full of people whose notion of a satisfactory future is, in fact, a return to the idealised past.

每个人在世界上都有一个位置要填补，并且在某些方面是重要的，无论他是否选择如此。

Collaboration in mathematics is essential; the exchange of ideas leads to breakthroughs that no single mind could achieve alone.

解释：先前所使用的，现在或许要抛弃。现在要抛弃的，将来或许会用到。