There is nothing "subjective" about Bayesian probability.
Because a direct contradiction of this quote is also true (and also something that the Jaynes would probably agree with) it is perhaps not the best 15 words in his work. The problem is that all the meaning conveyed relies on the reader plugging in suitable meanings for 'subjective' so that it makes sense. The knowledge needed to construct an interpretation of the quote that is correct and insightful gets deducted from the information that is conveyed by the quote.
I do agree that this message and this source are worth quoting. If the excerpt badger quotes does come from Jaynes then it certainly deserves a place. Same message, less ambiguity.
People want to tell everything instead of telling the best 15 words. They want to learn everything instead of the best 15 words. In this thread, instead post the best 15-words from a book you've read recently (or anything else). It has to stand on its own. It's not a summary, the whole value needs to be contained in those words.
I'll start in the comments below.
(Voted by the Schelling study group as the best exercise of the meeting.)