We can use 'would' to refer to 'what is very likely. We use it to show probability. These are some examples that I took from some dictionaries: He would be a teacher.
The guy on the phone had a Southern accent." "That would be Tom."
I think my swimming pool would [=could] hold 20,000 gallons of water.
So my question is can we use 'would have' to refer to those things which we think was very likely in the past?
As generally we use 'would have'in conditionals to talk about something that did not happen in the past.