Also, remember to apply even standards to evidence. If you flat out deny ufo eye witness accounts as being without epistemic value, also do this for all other eye witness accounts:
Your girlfriend says she saw an eagle over the creek? Didn’t happen. And don’t investigate any further.
Your friends talk about the beautiful yacht that left the harbor this morning? Flat out deny it. And don’t investigate any further.
Your kid eagerly tells you about the squirrel she just saw in the tree outside. Tell her you don’t attribute any truth value to her utterings. And don’t investigate any further.
If you don’t, you have a priori established double standards for the epistemic value of the same type of evidence. This is also known as ‘bias’.
If you think there’s an inconsistency in people’s dismissal of UFO eyewitness accounts, I think you may not have grasped the principles of Bayesian reasoning yet.
Eliezer’s introduction is here, but to add some subject relevant commentary:
Eyewitness reports of unfamiliar things tend to be much less reliable than eyewitness reports of familiar ones. If a person witnesses someone they already recognize committing a crime, for instance, their description of the perpetrator is likely to be highly accurate, whereas a person who witnesses someone they don’t recognize committing a crime is likely to give a description that’s extremely unhelpful, and often worse than useless.
So as a general principle, people reporting on unfamiliar phenomena tends to be weaker evidence than people reporting on familiar ones. If your girlfriend says she saw an eagle by the creek, and she often sees eagles and is well equipped to recognize them on sight, then her report is stronger evidence than that of a tourist who thinks they know what eagles look like, and saw a bird which fit their idea of what an eagle is supposed to look like, so they’re pretty sure that’s what it was, which is in turn stronger evidence than a report from someone who doesn’t know what eagles look like at all, but saw a bird which they think fit the description of an eagle which they heard after seeing it.
This is in addition to the fact that the single standard of Bayesian evidential reasoning demands larger amounts of evidence to raise less probable events to the point of likelihood. If seeing an eagle over the creek has a prior of .02, your girlfriend’s say-so is more than enough evidence to accept the proposition, unless she’s unusually dishonest. If she claims to have seen a gremlin, on the other hand, the prior is going to be much, much lower; if gremlins exist at all, they must be awfully rare and elusive to have avoided reliable observation thus far. So the likelihood that the report is due to misidentification, dishonesty, confusion, or some other reason for a false report, swamps the likelihood that she really saw a gremlin, under the same standards of evidence as we would apply in the case of the eagle.
The same goes for radar: Today air traffic controllers attribute epistemic value to radar data on the question of determining size and movement of objects in the sky. However, they really should ditch their equipment as we attribute zero epistemic value to the radar signals if the objects it detects move in ways that current man made objects cannot or if the objects are larger than current man made objects (say, with a diameter of two aircraft carriers. Right?
Also, remember to apply even standards to evidence. If you flat out deny ufo eye witness accounts as being without epistemic value, also do this for all other eye witness accounts:
Your girlfriend says she saw an eagle over the creek? Didn’t happen. And don’t investigate any further.
Your friends talk about the beautiful yacht that left the harbor this morning? Flat out deny it. And don’t investigate any further.
Your kid eagerly tells you about the squirrel she just saw in the tree outside. Tell her you don’t attribute any truth value to her utterings. And don’t investigate any further.
If you don’t, you have a priori established double standards for the epistemic value of the same type of evidence. This is also known as ‘bias’.
If you think there’s an inconsistency in people’s dismissal of UFO eyewitness accounts, I think you may not have grasped the principles of Bayesian reasoning yet.
Eliezer’s introduction is here, but to add some subject relevant commentary:
Eyewitness reports of unfamiliar things tend to be much less reliable than eyewitness reports of familiar ones. If a person witnesses someone they already recognize committing a crime, for instance, their description of the perpetrator is likely to be highly accurate, whereas a person who witnesses someone they don’t recognize committing a crime is likely to give a description that’s extremely unhelpful, and often worse than useless.
So as a general principle, people reporting on unfamiliar phenomena tends to be weaker evidence than people reporting on familiar ones. If your girlfriend says she saw an eagle by the creek, and she often sees eagles and is well equipped to recognize them on sight, then her report is stronger evidence than that of a tourist who thinks they know what eagles look like, and saw a bird which fit their idea of what an eagle is supposed to look like, so they’re pretty sure that’s what it was, which is in turn stronger evidence than a report from someone who doesn’t know what eagles look like at all, but saw a bird which they think fit the description of an eagle which they heard after seeing it.
This is in addition to the fact that the single standard of Bayesian evidential reasoning demands larger amounts of evidence to raise less probable events to the point of likelihood. If seeing an eagle over the creek has a prior of .02, your girlfriend’s say-so is more than enough evidence to accept the proposition, unless she’s unusually dishonest. If she claims to have seen a gremlin, on the other hand, the prior is going to be much, much lower; if gremlins exist at all, they must be awfully rare and elusive to have avoided reliable observation thus far. So the likelihood that the report is due to misidentification, dishonesty, confusion, or some other reason for a false report, swamps the likelihood that she really saw a gremlin, under the same standards of evidence as we would apply in the case of the eagle.
The same goes for radar: Today air traffic controllers attribute epistemic value to radar data on the question of determining size and movement of objects in the sky. However, they really should ditch their equipment as we attribute zero epistemic value to the radar signals if the objects it detects move in ways that current man made objects cannot or if the objects are larger than current man made objects (say, with a diameter of two aircraft carriers. Right?