At one point, naive Bayesian classifiers were considered machine learning. Now we use them for spam filters. Chess playing algorithms were also considered machi

At one point, naive Bayesian classifiers were considered machine learning. Now we use them for spam filters. Chess playing algorithms were also considered machine learning at one point. We keep moving the goalposts. We won't ever reach a specific point of concluding that we have intelligent machines. There won't be a breakthrough, much like living organisms never had an intelligence breakthrough; they just gradually became more and more intelligent through incremental development.