It’s simply that likelihood is relative to a model, whereas probability is not relative to anything
Likelihood is the probability of the data given the model, not the probability of the model given the data. A likelihood function gives you a number between 0 and 1 for every model, but that number does not mean anything like “how certain is it that this model is true”.
Likelihood is the probability of the data given the model, not the probability of the model given the data. A likelihood function gives you a number between 0 and 1 for every model, but that number does not mean anything like “how certain is it that this model is true”.