… weighs one gram … An amount of hydrogen weighing the same amount has exactly one mole of atoms in it.
Not only was this never true - the sentence would have to have say “An amount of carbon-12 atoms weighing 12 times this amount has exactly 1 mole atoms in it” (far less elegant) – but not even this is true any longer after the fuckup in redefining the mole in 2019, after which all these relations between amount of substance and mass are only approximate.
Ackchyually-- IEEE 754 guarantees any integer with absolute value less than 2^24 to be exactly representable as a single precision float. So, the “divide by 2, check for decimals” should be safe as long as the origin of the number being checked is somewhat reasonable.
While a broad concept, in the context of your question, science is a metod to derive knowledge from observations.
Alternatives to the scientific method is to guess or to obtain knowledge from others. (Most other ways I can come up with, e.g. “religion” can still be sorted under these two.)
Obtaining knowledge from others is great, but may not always be available, and the quality of the knowledge derived this way depends on the reliability of the source.
For the other alternative, every sensible metric shows how science is a better method than guessing to derive knowledge.
But, “speedy” relative to what? Relative to the walls of the room your are inside? What if you are in a falling elevator? Relative to the rotating surface of the earth? To the center of the solar system? “Relative to the portal” is the only answer to that question that makes sense.
How can it not be b? Every situation in the Portal games is already exactly like this, but with the portal fixed to a slab that moves with the rotation of the Earth, whereas in the drawing the portal moves as the sum of earth rotation + the movement of the train.
Treating the question seriously, I think it is easy to think the one person is the right choice, because it just seems like less of a mess to deal with. However, I also think the end result is that you will never feel safe in your home again. You will always second guess if every squeak you hear is yet another person who somehow have made it into your house. This is the path towards slowly descending into madness.
As a different, more techy, solution that can work depending on the people you collaborate with, is to use a hosted Git service for collaboration (if you want to stay completely open source, a self-hosted GitLab).
Then, change your publication workflow to write in Markdown, ReST, or one of the other ascii formats that previews correctly, and set up your CI to render the documents automatically into, e.g., pdf:s using a converter. There are all kinds of converters from Markdown/ReST -> docs, presentation, etc. formats that are as competent - if not more so - than the usual office suites. This setup offers both online editing in the GitLab instance and offline by local cloning of the Git repo.
The side effect is that this system very seriously records and preserve your document history. You can see exactly who, at what point, changed, added, and removed things. For some types of documents, this can be very important.
Nope, this redefinition isn’t necessary, it is a choice SI made. Nothing would have broken by keeping an exact relationship between amount of substance and mass, it would just have retained the interpretation of Avogadro’s constant from before 2019 (experimentally determined vs a defined constant).