The set of Possibilities is much greater than the set of what is Probable.
When communicating about the future and in making decisions, it’s important to distinguish the probable and possible. This is typically done by giving a low, medium, and high figure.
For instance, when asked, “how many visits is this page likely to get in the next month?”, I would set up my analysis so that I could give a low case (5% chance of happening) a high case (5% chance of happening) and a middle case (the midpoint in between). By being aware of the 1:20 and 1:20 bounds, I can make an attempt at checking delusional tendencies. That is to say, sometimes we are wildly optimistic – driven by hope. And, sometimes we are wildly pessimistic – driven by fear. Selecting the mid point, following a sensitivity analysis, is one way (not the only one) to mediate between the two effects.
Whenever somebody puts forward a claim that, at first glance, seems outrageous, you can help everybody involved by admitting that their claim is possible. This paves the way for what you really must do next: inquire about the underlining assumptions about why they believe in that claim. They may have a valid underlining model that you have not considered.
However, if their assumptions cannot stand up to your scrutiny, you can always say, “it is not probable” or “it is not likely” that their idea will work. And you’ll have done the most you can do to inform your own thinking.
