Living under the odds
Suppose you take the argument seriously enough to put a real probability on it. Not the authors' near-certainty, but not a rounding error either: something you would not bet your life against. What follows for how you live? This turns out to be a strange decision problem, and the usual tools handle it badly.
Why hedging does not work
Ordinary risk management assumes a world after the bad event in which you collect on the hedge. Insurance, diversification, a bunker: all of them are ways of moving resources from good states to bad ones. The binary outcome has no "after" in which anyone collects. You cannot insure against it, cannot diversify across it, and cannot prepare for it in any way that changes your experience of it. The book is right about this and says so, and it is worth internalising, because a great deal of energy gets spent on hedges that do not hedge.
There are two ways to respond to an outcome you cannot hedge. One is to try to reduce its probability, which is the Avoid section, and which is the only thing that functions as insurance for the binary case. The other is to notice that its existence changes the value of everything else, and to work out how.
What the total outcome does to the value of other things
It lowers the value of long-horizon investments, because a fraction of the futures they pay off in are gone. It does not zero them, because the non-binary worlds are still there and in most of them long-horizon investments matter more, not less. So the correct adjustment is a discount, not an abandonment, and its size is your probability.
It raises the relative value of things that pay off now or in every world: health, relationships, work you find worth doing, time with people you love. These are not consolations. They are the assets whose value is unaffected by the outcome you cannot hedge, which makes them the best investments available under uncertainty about it. A person who takes the argument seriously and responds by spending more of their life on what they would want to have spent it on anyway is reasoning correctly, not coping.
And it creates a specific class of action that is valuable only because of the total outcome: work that shifts its probability. For most people that is money and voice rather than research, and the amount it makes sense to give is proportional to the probability, which is a number you have to pick yourself. There is no avoiding the number. The book picks one for you; the argument pages here are an attempt to help you pick your own.
Two failure modes
The first is letting the number eat everything. If the probability is real, then any amount of present sacrifice seems justified by the stakes, and people who follow that reasoning end up with no life and, usually, no measurable effect on the probability. The authors' own entry, Are you saying we should panic?, says no, and means it. Panic is not a strategy and neither is total devotion, unless you are one of the few people whose devotion moves the number.
The second is the opposite: treating the total outcome as licence. If it might all end, why save, why plan, why sacrifice for a future? Because the future is still the most likely place you will be, on any honest probability, and because the non-binary bad worlds punish people who arrive at them with nothing. Nihilism is a mistake about the odds, not a response to them.
An attention policy
The question can consume unbounded attention and returns almost none of it as better decisions. A reasonable policy: decide what you believe, write it down with the reasons, and revisit it on a schedule, quarterly or when something genuinely new happens, rather than continuously. Between reviews, live according to the last decision. This is not avoidance. It is the same discipline a person uses for any risk that is real, slow, and mostly outside their control, and it is the difference between taking the argument seriously and being taken over by it.
What I would say in one paragraph
The total outcome cannot be hedged, only made less likely. Everything else can be. Discount the long term by your probability, not to zero. Overweight what pays off in every world. Give to avoidance in proportion to your belief and then stop thinking about it until the next review. And do not let the one outcome you cannot prepare for crowd out the many you can, since those are where your effort actually changes what happens to you.