Question

1. Anybody can make mistakes.
2. We can go to the concert.
3. We could go to the concert.
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In a grammar book, it is said that 'can' in #1 is used as theoretical possiblilty' Is that right? In #3, 'could' is used as 'present possibility.' What about 'can' in #2? Which one is the surer of the two.[#2 and #3] Does #2 have more possibility or does #3 have more possibility?
Can 'can' have both 'theoretical possibility' and 'present possibility'? What is the root of the terms of 'theoretical possibility' and 'present possibility'?

Answer 1

#1 is said to be theoretical possibility because of the word "Anybody." No one in specific is named as the subject.

#2 is present tense and means we are able to (but don't have to) go to the concert.

#3 is more of a possibility, especially when we are trying to decide what to do for the evening!