The Logical Fallacy that A implies B
This is an example of a "false cause" or "post hoc ergo propter hoc" fallacy.
i.e. "A occured, then B occured. Therefore A caused B"
- "The rooster crows every morning, therefore the rooster causes the sun to come up.
- "Hospitals are full of sick people. Therefore hospitals make people sick."
In this case:
- "Prussian Blue was used in woodblock paintings. Woodblock paintings were the precursor to manga. Therefore, the invention of Prussian Blue was critical to manga's creation"
The Actual Claim - A was faster than it could have been
We can break down the statement from the video:
Prussian blue reinvigorated Japanese wood block painting, which went on to influence manga which led to Japanese animation
If we look carefully at the facts from this sentence:
A: Prussian blue reinvigorated Japanese wood block painting
B: Japanese wood block painting went on to influence manga
C: manga led to Japanese animation
These are presented by the video as to seem to be connected, but they are not necessarily.
Let's imagine that artists took 100 years to perfect Woodblock Painting, then 100 years to develop Manga and another 100 to Anime. The entire time being 300 years to create Anime (note: these timelines are entirely made up)
Vsauce is implying that this first stage was invigorated and perhaps moved faster than it may have without the introduction of Prussian Blue. Maybe it would have taken 80 years to perfect Woodblock Painting instead - leaving us with a total of 280 years before we got to anime for the same process.
What they are saying isn't incorrect, but it is worded as to give Prussian Blue a false importance.
The new availability of blue ink did allow some new stylistic choices for authors, as an alternative to black. We can see artists chose this sometimes in other areas than Japan.