How fast is the Earth moving, and in what direction? How the ancient Greek philosophers were mostly wrong but blazed conceptual trails. And thought experiments that challenge conventional thinking.
In my post three days ago about whether a ship that has had all its parts changed out is really the “same” ship, I brought up the associated idea of whether a “place” on Earth is the same from moment to moment, given that motion of the Earth in various directions. Cue this piece, that I saved from Facebook a while back.
Big Think, Ethan Siegel, 16 March 2022: How fast does the Earth move?, subtitled “It rotates on its axis, revolves around the Sun, moves throughout the Milky Way, and gets carried by our galaxy all throughout space.”
The article considers how fast the Earth spins, how fast the Earth moves around the Sun, how fast the Solar System moves through the Milky Way, how fast the Milky Way moves within the Local Group, and how fast the Local Group moves through intergalactic space. And comes up with an answer: 42.
Just kidding! Actually this:
Overall, our total motion through space comes out to about 368 km/s in a particular direction: toward the constellation of Leo. Over the course of a year, this can vary by as much as ~30 km/s, driven largely by the Earth’s changing motion around the Sun. This is confirmed by measurements of the cosmic microwave background radiation, which appears preferentially hotter in the direction we’re moving (toward Leo), and preferentially colder in the direction opposite to our motion (away from the constellation of Aquarius).
With appropriate qualifications.
Big Think, Scotty Hendricks, 23 Feb 2023: 7 Greek philosophers and their brilliantly flawed explanations of nature, subtitled “Though ultimately incorrect, the ancient Greek philosophers blazed a conceptual trail for humankind to understand the nature of reality.”
I also mentioned in that post three days ago that “ancient philosophy is mostly based on presumptions (guesses) about the world that have turned out to be false.” It took a millennium and a half (while enduring religious domination and censure) before it occurred to “natural philosophers” (later called scientists) that their notions could be tested against reality by experiment. This article is a nice summary of the (very familiar, to anyone with a glancing knowledge of the history of philosophy) notions of early Greek philosophers.
Again, the Key Takeaways:
The Greek philosophers pondered everything, but some really wanted to know what the world was made of. The search for the arche — the first principle — led to the invention of many key ideas in philosophy. In the end, the Greeks made major advances, even if they were all ultimately incorrect.
The familiar set: Thales and water; Anaximander and “apeiron”; Anaximenese and air; Heraclitus and fire; Parmenides and the world as illusion; Democritus and atoms; Plato and forms. Plato, the article concludes, is the closest to have gotten things right.
Big Think, Scotty Hendricks, 15 Feb 2023 (updated from Apr 2018): 7 thought experiments that will make you question everything
Some of these are familiar to me, in particular John Rawls notion of justice, from 1971:
Suppose that you and a group of people had to decide on the principles that would establish a new society. However, none of you know anything about who you will be in that society. Elements such as your race, income level, sex, gender, religion, and personal preferences are all unknown to you. After you decide on those principles, you will then be turned out into the society you established.
Question: How would that society turn out? What does that mean for our society now?
This thought experiment is one of the drivers of current thinking about morality, from Sam Harris, Michael Shermer, and others.
Several of these are familiar, and involve moral or ethical conundrums which traditional morality cannot easily solve.
The “Swampman” query from Donald Davidson goes to the many science fictional debates about whether a Transporter, like the one in Star Trek, preserves the original or merely replaces it with an identical copy. I had not heard about the “Thompson’s violinist” but it’s a powerful analogy to the issue of abortion. Robert Nozick’s “Experience Machine” also aligns with many science fictional thought experiments, and notions of VR and Trek’s holodeck.
Frank Jackson’s “Mary’s Room” query about knowledge also invokes many science fictional ideas about ideas or perceptions human beings are unaware of, as well as contemporary studies like Ed Yong’s An Immense World about all the many things other animals perceive that human beings cannot.
And Peter Singer’s “life you can save” again goes to modern ideas of morality… and the ideas of the effective altruism movement. How close or far do you extend your personal circle of morality?