Some decades ago I found a card that changed my thinking.
One side said "The statement on the other side of this card is true."
The other side said "The statement on the other side of this card is false."
Current thinking:
A fantasy statement only connects to other words, not reality.
A true statement agrees with reality.
A false statement contradicts reality.
Therefore the card had two fantasy statement.
Once it is determined that a statement falls somewhere on the true-false spectrum, the three acceptable methods I know to find where are:
The judicial/historical method asks whether we have reliable witnesses and accurate records of their testimony.
The experimental method asks whether the evidence can be repeated, as in experiments or another observation.
The predictive method asks whether the statement makes a prediction that can be tested.
If you know another good method, please post it
Since none of us knows everything, we are not going to get everything correct. What disturbs me is how often people make important statements and don't discuss what would be needed to test them. The test methods are more important than whatever conclusions are reached.
Note that the historical method is critical - incorrect reports of experiments, observations, or possible predictions work against good results.
So I try to find killer questions:
A killer question relies on correct knowledge, then asks something that allows a good test. Especially it allows testing between the multiple paradigms that can be attached to any given set of facts.
Example 1: If cold fusion experiments do produce the extra heat claimed, possible paradigms range from actual cold fusion, through the accidental construction of an antenna that can collect cosmic energy (a la "Doc" E. E. Smith), to a fantastic one that Bahzell's multiverses exist and a magician is fooling us. Or the major fantasy that they stumbled on a hole in the conservation of energy paradigm.
Are there fusion products
Example 2: from early in this thread, Noah's flood. Sedimentary rocks cover about 75% of the continents and continental shelves. Average depth estimates range from 5 miles to 8 miles, with some places baring the basement rock, others as much as 20 miles thick. Base rock covered with sediment doesn't erode until exposed.
Where did the material come from
At one end of the ideas, start with mountains over 20 miles tall. In the middle assume standard erosion covering and uncovering the base rock. At the other end, assume a miracle that lifts up sediments and erodes base rock.
It should be possible to test this with a detailed examination of the sedimentary rocks. Mountains and multiple standard erosion would tend to produce gullies and canyons, while a world wide flood strong enough to product that much erosion would be expected to produce flattish strata as the dominant form. These strata could be traced over long distances.
Interestingly the Institute for Creation Research is the only one I know that is testing this. Among other things, they found reports that in the Grand Canyon Redwall shale formation, some long thin fossils are leaning the same direction across distances of several hundred miles.
Can't we suggest methods of testing when we say things?