This brought in their writing skills. After we talk about all of them, we will write the numbers down - now this is three and two more - before we even tell them the plus sign, you know,how to join things together."

VOA: standard.2010.08.10

We are able to talk about the fact that two plus one equals three, but it's not as though we ever come across numbers-- number three itself--anywhere in the empirical world.

我们可与去探讨,二加一等于三的这个事实,但是我们不可能有一天真的碰到数字,在现实世界中碰到个叫"数字三"的东西

耶鲁公开课 - 死亡课程节选

We all do believe something makes it true that two plus one equals three, but it's not the fact that empirical objects-- We don't do empirical experiments to see whether two plus one equals three.

我们都相信有些东西,使2加1等于3是正确的,但这不是说现实的东西,我们不会在现实中做实验,去看看二加一是不是等于三

耶鲁公开课 - 死亡课程节选