This question came to mind when I was dealing with this question: A card from a pack of 52 cards is lost. From the remaining cards of the pack, two cards are drawn at random and are found to be clubs. Find the probability that the lost card is a club.
My query: The probability that a club is lost is $13/52$. The next event of taking two cards from this incomplete set of cards happens after one of the cards is lost. How can this affect a past event of losing a card from the pack?
The event has not changed. Your information regarding the event has changed.
For instance, say you were interested if the Club Ace was lost.
Now if the two cards happen to have the Club Ace, would your estimate of the chances still be as before?
Basically, the probability is based on what information you have at hand.