At what point did Python become the tool for developing neural networks, and not Prolog?

Prolog was not designed for that.

Python is just used to e.g. load data and call a neural-network API. Which Prolog could do… but there’s no advantage in using Prolog for just that, and Python is basically easier to code in.

Prolog excels in rule-based systems, where we specify the rules.

Neural networks have no fundamental understanding of logic (or arithmetic), so often create good-looking rubbish, so cannot be trusted.

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