Interpretation of ambiguous sentence "You Can’t Put Too Much Water into a Nuclear Reactor"

Question

"You Can’t Put Too Much Water into a Nuclear Reactor"

This sentence is from a book, "The Definitive ANTLR 4 Reference" authored by Terence Parr.

The author used this sentence as an example of ambiguous sentence and mentioned that it can be interpreted in two ways.

(1)They should be careful not to put too much water.

(2)They should put lots of water into the reactor.

But I can't see how to interpret it in way of (2). How should I do it?

When I interpret it in way of (1), I see the words "Too Much Water" is one group and noun, and I can't put it into "Nuclear Reactor".

Answer 1

The sentence is ambiguous because "you can't" could mean "it is extremely inadvisable to" or "it is impossible to." In the first interpretation, the sentence becomes a warning against an excess of water; in the second, it becomes an encouragement to use as much as possible.

Consider these uses similar to the first case:

• You can't park here.
• You can't swim in this weather.
• You can't let Mom find out.

And these similar to the second:

• You can't thank her enough.
• You can't convince me otherwise.
• You can't imagine what it's like.

Many uses of "can't" are technically ambiguous but the meaning is obvious in context. Then again, I thought the sentence you posted was obviously the second usage and you were sure it was the first.

You can't be too careful choosing your words.