The sophists were ancient greek and athenian orators who were brilliant at convincing others that their arguments were correct. The sophists were generally reviled among the ancient philosophers because they did not care as much about truth than they did about simply winning the argument.
One of the tactics that the sophists would use was repetition. Jamie Dimon appears to be reverting back to this tactic when he calls bitcoin a fraud. He called bitcoin a fraud when bitcoin was worth $400 per coin. Now that it is worth over $4,000 per coin he is once again repeating the same argument, without even acknowledging that he said the same thing years ago....and successfully avoided a 1,000 percent gain for his clients as well (does that anger him? One wonders?).
Mr. Dimon refers to bitcoin as a fraud and a bubble waiting to pop. However, bitcoin has only grown in size and global use and growth since he began attacking it - his bank on the other hand, was on the verge of bankruptcy and required a $12 billion dollar hand-out of taxpayer money to stay afloat.
He speaks of a bubble because of increased adoption of an immutable instantaneuous method of transferrring value that is beyond government's control, which has no debt and a define limit...but does not believe that the US currency which now has 20 trillion dollars of debt behind it (could that ever be repaid?). Does that make logical sense?
If Bitcoin succeeds in its original philosophical mission, there will be no one to bail his bank out the next time that it fails - no way to secretly have ordinary taxpayers foot the bill of his failure. Does that influence his comments?
Bitcoin and crypto-curency in general is giving birth to new manners of company funding, new players, new ways of cutting out banks and large institutions from taking fees to "manage" funds, it is levelling a playing field where the banks arguably leverage a privileged position in the stock market that many commentators have criticized.
Perhaps Mr. Dimon has good reason to criticize bitcoin - self-interest.