From: raghu
Oh boy, lets see if I can keep this straight (:-). A tautology is a logical necessity. An empirical truism is not necessarily a tautology. The statement: "the GDP of a growing economy always increases in time" is a tautology, but "CEOs make a lot of money" is not, though they are both true. At some philosophical level, it can be argued that there is no difference between the two, but I won't go there. To start with, not *some* bubbles but *all* bubbles are caused by speculators. This statement indeed is a tautology because it follows from the definition of a bubble. ^^^^ CB: Yes, lets start over here. ^^^^^ > Does anything besides speculators predominantly betting on rising > prices create bubbles ? No. ^^^^ CB: Ok. ^^^^ > It not a tautology that speculators always and everywhere create > bubbles. Whenever and wherever there is speculative money available, a > bubble is absolutely inevitable. > > ^^^^ > CB: Is the second sentence supposed to be "not absolutely inevitable " > ? Otherwise, it seems to contradict the first sentence. Should the > first sentence be " It is not true that speculators always and > everywhere create bubbles ? There is no contradiction. The second sentence is not a *logical* necessity but an *empirical* fact. It is conceivable that speculators could exist and not cause bubbles. A casino, for e.g. does not have any "bubbles". ^^^^^ CB: I'm thinking, thinking...It is not true tautologically or empirically that speculators always and everywhere create bubbles, i.e. it is not true that all speculators create bubbles. But all bubbles that come about are created by speculators; whenever there is a bubble, it is created by speculators,not by some other cause. In logical form: If there is a bubble, then it is created by speculators ( modus ponens) Not speculators, not bubble or no speculators , not bubble. Speculators are a necessary condition of a bubble. Bubbles are a sufficient condition of speculators. ^^^^^ > I don't think this point has been well recognized. The consensus seems > to be that speculators *sometimes* cause bubbles when they go out of > control. Not true. > -raghu. > > ^^^^^ > CB: Are you saying all bubbles are created by speculators ? > > or Speculators never fail to create bubbles ? Yes to both. The first is a trivial observation, the second not trivial. -raghu. This would be stronger than modus ponens above. Speculators and bubbles are equivalents, identical In logical form Speculators <===> Bubbles There would be an identity between them. But I don't think you mean this because you said that speculators in a casino don't create bubbles. So, that is a case where speculators fail to crreate a bubble. Do you mean speculators on the stock market always create, never fail to create bubbles ? -- _______________________________________________ pen-l mailing list [email protected] https://lists.csuchico.edu/mailman/listinfo/pen-l
