Presume I have a machine that, when you press a button, will either light up the red light bulb or the green light bulb. Usually, the red light bulb lights up, but the green bulb will if and only if one of the following two things are true: #1. The lottery ticket in your pocket is the winner of the big jackpot #2. It's raining.
You press the button. The light bulb turns green. There's no windows to check for rain or internet to check for winning numbers. You have no further information beyond the fact that the light bulb turned green.
Which is more likely to be the case: That you're now a millionaire, or that you should grab an umbrella as you leave?
We know we saw 'Oumuamua (the green light). We now can construct many models for why we might see such results. The probability that we would see the results given the model (lotteries or rain) can be used to infer what the true model most likely is.
You press the button. The light bulb turns green. There's no windows to check for rain or internet to check for winning numbers. You have no further information beyond the fact that the light bulb turned green.
Which is more likely to be the case: That you're now a millionaire, or that you should grab an umbrella as you leave?
We know we saw 'Oumuamua (the green light). We now can construct many models for why we might see such results. The probability that we would see the results given the model (lotteries or rain) can be used to infer what the true model most likely is.