It's really interesting how he constructs a self-consistent narrative with half true and half false premises.
For example, he totally whiffs on the geology due to bad starting premises. At this time, the Earth was believed to be relatively young (on the order of millions of years) because simple calculations would show that even a very high initial temperature would have cooled to at most the surface temperature within that time. What they missed was the internal heat budget of the planet, which we now know is driven by radioactivity (which, in 1907, had just been discovered - the Curies had shared a Nobel for it in 1903).
Wallace was right that this is a very small contributor to Earth's surface temperature, but the false assumption that the planet had dramatically cooled was behind the idea that continental shapes and faulting were due to the movement of a cooling and thus contracting planet. Plate tectonics was a few years away from even being proposed as a serious theory at this point, and it wouldn't gain much traction for another fifty years after that. But it turns out that tectonics is responsible for a lot of the geographic differences between the three bodies under discussion here. Earth has plate tectonics today, Mars probably did early in its history but does not today, and the Moon never did.
Yet despite being totally wrong about this, Wallace is correct (as best we currently understand it) that the Martian valleys are indeed fault lines. He comes around to it from a totally wrong direction: that Mars, being smaller than the Earth, began with less heat, and that its interior solidified first, causing its surface to contract onto that rigid surface and crack in a way Earth's did not.
There's a lesson here in the ability to form consistent, empirical, wrong theories given even slightly wrong inputs.
> There's a lesson here in the ability to form consistent, empirical, wrong theories given even slightly wrong inputs.
Is this really a lesson? Every single theory evolved this way, starting with an almost certainly naive hypothesis, then with incomplete evidence leading to bad conclusions, then as better data came in, adjustments to the theory until we had something that fit the evidence to a high degree (though it's almost always possible further adjustments are necessary even when it looks like we've found the perfect theory: e.g. Newton physics VS relativity).
I think you would be hard pressed to find any theory that did NOT evolve in this exact manner.
Yes it’s a big lesson, not so much in noticing other examples in the past but in thinking critically about present day conjectures yet to be resolved.
So many smart, credible people build up lines of thinking (a necessary step and best that can be done presently) around subjects. These get discussed, reported on, worked with, and very easily become conventional wisdom. Yet so often they turn out to be way off course.
I think it is a lesson, yes. It's not a lesson to avoid trying to form theories. It's a lesson in the importance of out-of-model error and in assigning low confidence to arguments with many premises and logical steps along the way, because each premise and each step creates new ways to introduce small propagating errors.
Self-consistent narratives generated with half-truths and false premises describes one heck of a lot of philosophy and theology, something I note being current with Peter Adamnson's History of Philosophy podcasts, inclusive of Western and other traditions (Indian and Africana being completed, Chinese just having launched).
That's not to denigrate all philosophy (much of it is useful, and even the wrongheaded stuff often contains useful methods and constructs in testing arguments and beliefs), or even the wrongheaded bits (useful not only as bad examples but also to explain much of current belief and ideology, and to show origins of contemporary arguments and topics). But it does provide a strong caution about the dangers of leaping off into rational thought with parlous thin empirical foundation, or of false premises. Wrong belief is often far more harmful than no belief.
As to Mars's characteristics ... I'm sufficiently old to have seen an immense evolution of understanding about the Solar System and Earth itself. In the mid-1960s, the theory of plate tectonics was just being formally accepted, the far-side of the Moon mapped for the first time (the story of National Geographic's map project published in 1969 is a wonderful account of this: part 1 <https://web.archive.org/web/20090129220141/https://kelsocart...> part 2 <https://web.archive.org/web/20090130150935/https://kelsocart...>) The Luna, Mariner, Zond, and Surveyor missions provided first close glimpses of the Moon, Venus, and Mars from the late 1950s to early 1970s. The Viking Mars landers (1975) and Voyager outer-planetary missions (1979--1988) absolutely revolutionised understanding, and that based on what was often just a very narrow and short glimpse. But the books I'd read as a child, published from the 1950s to early 1970s are now woefully out of date.
In fact, the most wrong assumption in the entire paper is that _canals existed at all_. Any fault lines on mars wouldn't have been visible from the telescopes they had at the time. The "canals" where in fact either optical illusions or streams of dust blowing around from wind.
The primary point of the paper is to dismiss the possibility that mars was habitable which he did quite effectively with basic thermodynamics, chemistry and geology, and the secondary point was to offer alternative explanations to explain what people were observing. Those alternative explanations weren't really necessary to achieve his primary point.
Not proposing little green men who are unlikely but suggesting there may be bacteria like organisms underground which seems quite possible. A reason I think Musk shouldn't be allowed to build a human settlement there in a hurry. It should be more like a national park with no biological humans. We can always have robots and FPV goggles for the visitors.
Chapter VI has an irritating equation that claims the fourth root of one-hundredth equals one-sixth. It should be obvious even without the help of any computing aid that this is wrong. Was it a typo or what else may have led to that mistake?
The denominator of that fraction is meant to be interpreted as what we would write today as 3.2, not 3x2, and indeed fourth root 100 = about 3.16. The interpunct (the mid-line dot you're interpreting as multiplication) was historically a common way of marking what we now mark with a . character.
I wouldnt mind a bot writing a comment on HN if it's thoughtful, which is HNs trademark. These comments are so damn void of any thought. You can flag them for being thoughtless alone.
It's one of the more spectacular cases in which I think Munroe utterly missed the plot. It's not that it's possible to create bots which at a superficial assessment are making constructive / helpful comments. It's that bots which do this often have covert goals or purposes, "alignments" in the LLM/ML context. These might or might not be known or evident to either the bots' creators or users, and might even be exploited by still other parties.
But bots are capable of a scale of operations which fundamentally changes the community dynamics of sites such as HN (or of Reddit, Twitter, Facebook, TikTok, etc., etc.). It also fundamentally violates the prime directive of HN, "[T]o make thoughtful comments. Thoughtful in both senses: civil and substantial":
For example, he totally whiffs on the geology due to bad starting premises. At this time, the Earth was believed to be relatively young (on the order of millions of years) because simple calculations would show that even a very high initial temperature would have cooled to at most the surface temperature within that time. What they missed was the internal heat budget of the planet, which we now know is driven by radioactivity (which, in 1907, had just been discovered - the Curies had shared a Nobel for it in 1903).
Wallace was right that this is a very small contributor to Earth's surface temperature, but the false assumption that the planet had dramatically cooled was behind the idea that continental shapes and faulting were due to the movement of a cooling and thus contracting planet. Plate tectonics was a few years away from even being proposed as a serious theory at this point, and it wouldn't gain much traction for another fifty years after that. But it turns out that tectonics is responsible for a lot of the geographic differences between the three bodies under discussion here. Earth has plate tectonics today, Mars probably did early in its history but does not today, and the Moon never did.
Yet despite being totally wrong about this, Wallace is correct (as best we currently understand it) that the Martian valleys are indeed fault lines. He comes around to it from a totally wrong direction: that Mars, being smaller than the Earth, began with less heat, and that its interior solidified first, causing its surface to contract onto that rigid surface and crack in a way Earth's did not.
There's a lesson here in the ability to form consistent, empirical, wrong theories given even slightly wrong inputs.