Ian writes: "I have yet to knowingly or deliberately use AI, as it falls into the category of things to avoid until there's no longer a choice, which I suspect is already the case. I've noted the AI results in search engines, which are sometimes wrong. As you indicate, the concern with the exponential growth of AI is its frivolous use, which undermines its potential value. Perhaps there needs to be, as economists would say, a 'price-signal'. Under the time-honoured 'polluter-pays' principle, AI supported by fossil fuel energy should cost more to allow for the externalities of downstream pollution of...