I often think of Galen better known as Galen of Pergamon, a prominent Greek physician, surgeon and philosopher in the Roman Empire. While accomplished of all medical researchers of antiquity, might be a strange person to dwell, he influenced the development of various scientific disciplines, including anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy and logic. The problem was that as good as Galen was, his book was never updated for more current information. Centuries after Galen’s death, his book was taken as the book on medicine and when later scholars like Paracelsus disagreed with Galen, they were told that what they saw did not matter as it disagreed with Galen and Galen, they felt was truth hence, anything disagreeing with Galen was wrong. (There is a fascinating discussion of this in Daniel Boorstein’s, “The Discovers”, a book I highly recommend..)
This does not seem so far from the idea of alternate truths, and that today, with the internet one can find a source to back up whatever claim one makes. No matter how ludicrous a claim is made, it seems that someone can find some internet source to back it up. While, with Galen, it took years for the truth to will out, it now seems that we have a moving target in the realm of Alternate truth. Whereas with Galen, there was a finite monopoly on truth, the book was written and so his truth was determined. However today it seems that we have levels of truth, a tweet does not convey the truth but requires an interpretation and revision with a parade of soothsayers needed to discover the real meaning of the truth. Oddly enough, it seems that this was the initial objective of Galen.