Having the prediction turn out doesn’t make the theory true or more likely, it is just consistent evidence. There are an infinitude of other theories that the same evidence is consistent with.
To give a simple example, consider flipping a coin. You observe HHH. Is this a fair coin? or a double-headed one? or a biased coin? Different theories describe these situations, and you could be asked to bet on them. Imagine you then further observe HHHH—making a total of HHHHHHH. This makes your estimate of the chances of the “double-headed coin” hypothesis go up. Other hypotheses may increase in probability too—but we are not troubled by there being an infinity of them, since we give extra weight to the simpler ones, using Occam’s razor.
Having the prediction turn out doesn’t make the theory true or more likely, it is just consistent evidence. There are an infinitude of other theories that the same evidence is consistent with.
To give a simple example, consider flipping a coin. You observe HHH. Is this a fair coin? or a double-headed one? or a biased coin? Different theories describe these situations, and you could be asked to bet on them. Imagine you then further observe HHHH—making a total of HHHHHHH. This makes your estimate of the chances of the “double-headed coin” hypothesis go up. Other hypotheses may increase in probability too—but we are not troubled by there being an infinity of them, since we give extra weight to the simpler ones, using Occam’s razor.