If you aren't in over your head, how do you know how tall you are?

What is your identity, and how do you know who you are if you don't have language?

It's not wise to violate rules until you know how to observe them.

Knowledge is invariably a matter of degree: you cannot put your finger upon even the simplest datum and say this we know.

How do you know you're going to do something, untill you do it?

The point is, how do you know the Guarantee Fairy isn't a crazy glue sniffer.