There's a great article in the New Yorker about how life's biggest decisions seem to...just kind of happen. There's a short round-up of books and articles considering the paradox, some explaining it in terms of not knowing what the thing you want will actually be like, some by examining how aspiration is really meta-wanting (wanting to want something), and some by pointing out that our values and goals change over time in ways we could not have predicted ahead of time. On this last point I would superimpose a mechanism of biological imperatives; you don't decide to start wanting kids any more than you decide to get a carb craving.
I've noticed a similar experience with not having access to my own calculations, more for my decision to become a physician than to become a dad, although even with fatherhood, why now, here, with this person, is similarly hazy.
1. In public discourse, usually, most people do not have valence differences when they disagree, but rather differences of priority. This is especially true in politics. Concrete example: most people agree that racism is bad. The disagreement tends to be about how important it is to eliminate racism right now, relative to other problems. A valence disagreement occurs in this case when a white supremacist says no, actually, racism is good. Valence disagreements are of course much more intractable. Online discourse over the past few years has raised disagreements about priority to the same level of intractability, by turning priority disagreements into valence disagreements, e.g., "You shouldn't be talking about anything else right now but keeping out illegal immigrants. I don't care if you say you're against illegal immigration, if fighting illegal immigration isn't your number one priority, then you're actually for illegal immigration."
2. One trick to make your argument demand top priority is to claim that there is a massively, or even infinitely negative consequence for not adjusting one's actions in the ways required of a rational actor if the argument is true - or claiming that there is such a consequence even for ignoring the argument. Organized religion makes the most famous such claims, but the outcomes feared by certain political ideologies (if they don't get their way) can approach the same severity. This is the Gambit of Extreme Negative Utility (GENU.) Related to this, a counterargument to Pascal's wager is that you don't know which version of which religion is the right one, but as I saw a very clever Christian argue online, you have to assume infinite religions to choose from for the expected utility to work out in favor of ignoring Pascal's claim (although this still doesn't tell us which one to choose.) So what do we do? Do we set an arbitrary cut-off for utility beyond which we assume someone is lying to get our attention? This seems very dangerous, unless we think there are no rare events with far greater negative utility than we expect beforehand. So if we throw out Hell, Orwell's boot on a human face forever, and white supremacists' fear of a world overwhelmed by non-white barbarism, don't we also have to stop worrying about the Great Filter, the technological singularity, and CRISPR-derived biological weapons made by suicide cults?
3. It matters what arguments we consider, because although humans seem to have an implicit assumption of infinite time and attention to consider arguments, of course we do not.
From Bar-On, Phillips, and Milo in PNAS, 2018. Immediate stats that come to mind which are maybe more applicable to astrobiology: how many calories (or molecules or glucose) produced per unit energy of sunlight, per unit mass of plants? How about per overall energy produced by the sun (decreased by distance from sun and cloud cover on Earth)? How about base pairs per unit mass of taxon? Viruses probably win that one handily. And finally - an animation over time, where we see the branches appear, mass extinctions, and finally at the end a blossoming of birds and mammals which is really just livestock (or DOES livestock actually out-mass the pre-Holocene wild mammal and bird mass?)
The only thing here that really surprises me is that molluscs are higher mass than I expected, and nematodes lower mass.
"...there is good and bad speculation, and this is not an unparalleled activity in science...Those scientists who have no taste for this sort of speculative enterprise will just have to stay in the trenches and do without it, while the rest of us risk embarrassing mistakes and have a lot of fun." - Dan Dennett