In many industries if we redefined probability it would be considered malpractice or fraud.
We expect our doctors not to tell us we have a good chance of surviving surgery when we only have a 20% chance of surviving.
I would be fraud (I assume) for a lottery to tell someone buying a ticket that they have a good chance of winning millions (0000000.1% probability that you will win but a 75% probability that it will be won tonight by someone ).
i thought more of a technical argument, if this comment is based on stuff like "Event A and not A are both extremely likely".
I also think that both of your examples are not really useful, they don't violate the laws of probability. What a good chance is depends on more things than just the raw probabilities, for example i could phrase a ticket with a good chance as E(reward - price) > 0 (so its independent of its actual probability).
I don't consider "Event A and not A are both extremely likely" as P(A) != 0.5, communicating probabilities is not a mathematical problem, especially if words like "extremely" are used. Maybe P(A)=0.3 might also be extremely likely for your target audience.
Using your argument...what's a good chance of dying? It depends on the interpretation of the layperson and needs carful wording.
I remain faithful that his actual models are sound.
Actual probabilities are uncertain. If you think of the probability distribution on probabilities (the Bayesian prior), the claim that "one of the extreme probabilities is more likely than a halfway one" makes sense, eg. [0]
It makes more sense philosophically to make claims about one's model than about the real world, anyway.
"I don't consider "Event A and not A are both extremely likely"
To me, a 20% probability is not "extremely likely", but it is "extremely possible". A 10% probability is "quite possible" or "not terribly surprising". An 80% probability is "very likely", but perhaps not "extremely likely".
We expect our doctors not to tell us we have a good chance of surviving surgery when we only have a 20% chance of surviving.
I would be fraud (I assume) for a lottery to tell someone buying a ticket that they have a good chance of winning millions (0000000.1% probability that you will win but a 75% probability that it will be won tonight by someone ).