Gettier Problem - More General Gettier-style Problems

More General Gettier-style Problems

The "no false premises" (or "no false lemmas") solution which was proposed early in the discussion, proved to be somewhat problematic, as more general Gettier-style problems were then constructed or contrived, in which the justified true belief does not seem to be the result of a chain of reasoning from a justified false belief.

For example:

After arranging to meet with Mark for help with homework, Luke arrives at the appointed time and place. Walking into Mark's office Luke clearly sees Mark at his desk; Luke immediately forms the belief 'Mark is in the room. He can help me with my logic homework'. Luke is justified in his belief; he clearly sees Mark at his desk. In fact, it's not Mark that Luke saw; it was a marvelous hologram, perfect in every respect, giving the appearance of Mark diligently grading papers at his desk. Nevertheless, Mark is in the room; he is crouched under his desk reading Frege. Luke's belief that Mark is in the room is true (he is in the room, under his desk) and justified (Mark's hologram is giving the appearance of Mark hard at work).

Again, it seems as though Luke does not "know" that Mark is in the room, even though it is claimed he has a justified true belief that Mark is in the room, but it's not nearly so clear that the perceptual belief that "Mark is in the room" was inferred from any premises at all, let alone any false ones, nor led to significant conclusions on its own; Luke didn't seem to be reasoning about anything; "Mark is in the room" seems to have been part of what he seemed to see.

To save the "no false lemmas" solution, one must logically say that Luke's inference from sensory data does not count as a justified belief unless he consciously or unconsciously considers the possibilities of deception and self-deception. A justified version of Luke's thought process, by that logic, might go like this:

1. That looks to me like Mark in the room.
2. I don't think any factor, right now, could deceive me on this point.
3. Therefore, I can safely ignore that possibility.
4. "Mark is in the room," (or, 'I can safely treat that as Mark.')

And the third step counts as a false premise. But by the previous argument, this suggests we have fewer justified beliefs than we think we do.

In another example, Matthew drives through an area that appears to have many barns. In fact it contains a great many realistic barn facades, perhaps made to help shoot a Hollywood movie 'on location'. When Matthew looks at the one real barn along his route, he forms the allegedly justified true belief, 'There's a barn over there.' But if he follows the strong requirement for justified belief, then his thought process will follow the previous mentioned steps exactly. A similar process appears in Robert A. Heinlein's Stranger in a Strange Land as an example of "Fair Witness" behavior.