There are a couple of observations about markets, really observations about human decision making, which allow us to "shortcut" certain expensive pricing functions on ideas. ## Occam's razor Simpler explanations are more likely to be correct; avoid unnecessary or improbable assumptions. ## Hanlon's razor Never attribute to malice that which can be adequately explained by stupidity. ## Hitchens's razor That which can be asserted without evidence can be dismissed without evidence. ## Hume's guillotine What _ought_ to be cannot be deduced from what _is_. "If the cause, assigned for any effect, be not sufficient to produce it, we must either reject that cause, or add to it such qualities as will give it a just proportion to the effect." https://en.m.wikipedia.org/wiki/Philosophical_razor