So the common sense picture of reality, that the world is really the way it looks to us, Descartes shows that we cannot just assume this to be true beyond all doubt.

所以关于现实人们普遍认为世界就是我们所看到的样子，笛卡尔表示我们不能不经质疑地认为这是真的。

youdao

But this happens to be completely legitimate, so I'm going to assume it's true and I'll maybe take a second explaination why it's legitimate.

但这里所说的情况是完全合理的,所以我先假设这是对的,待会儿再进一步解释为什么合理

耶鲁公开课 - 基础物理课程节选