Evaluating Theories: The TEST Formula Step 1: State the Theory and check for con

Evaluating Theories: The TEST Formula
Step 1: State the Theory and check for consistency. Step 2: Assess the Evidence for the theory.
Step 3: Scrutinize alternative theories.
Step 4: Test the theories with the criteria of adequacy.
A Doomed Flight
In 1996, a Boeing 747 jetliner known famously as TWA flight 800 crashed in the At- lantic Ocean off Long Island, New York, killing all 230 people onboard. The incident, like most airline disasters, prompted a search for explanations for the crash and the proliferation of numerous explanatory theories, some of them alleging conspiracy, cover-up, and dark deeds. The FBI, the National Transportation Safety Board (NTSB), and others launched investigations, relying heavily on the criteria of adequacy to sort through competing theories. After many months of inquiry and debate, experts concluded that the probable cause of the crash was mechanical failure.
Using this incident as inspiration and guide, let’s devise another story of a mys- terious jetliner crash and examine the main theories to explain it. We will assume that all the facts in the case are known, that all relevant reports are honest (no in- tent to deceive), and that no other information is forthcoming. In other words, this is a very contrived case. But it suits our purposes here just fine. Here goes.
A Boeing 747 in trouble; from the movie Eraser.
The (made-up) facts of the case are these: At 7:30 p.m. flight 200, a Boeing 747, departed JFK airport in New York on its way to London and then crashed into the Atlantic about thirty miles off the coast. While in flight, the plane exploded, sending debris over a wide area. The crash hap- pened during a time of height- ened awareness of possible terrorist attacks on aircraft.
Now let’s try steps 1–4 on a supposedly popular theory and some of its leading alternatives. Here’s the pop theory in ques- tion. Theory 1: A missile fired by a terrorist brought down the plane. This one meets the requirement
CHAPTER 9 | Inference to the Best Explanation
for consistency, so our first concern is to assess the evidence for the theory. Those who favor this theory point to several pieces of evidence. Eyewitnesses said that they had seen a bright streak of light or flame speeding toward the plane. A few people said that they thought they were watching a missile intercept the plane. And a journalist reported on the Internet that the plane had been shot down by a missile fired from a boat.
There are, however, some problems with this evidence. Eyewitness reports of the movements of bright lights in a dark sky are notoriously unreliable, even when the eyewitnesses are experts. Under such viewing conditions, the actual size of a bright object, its distance from the observer, its speed, and even whether it’s moving are extremely difficult to accurately determine by sight. Also an- other phenomenon could have easily been mistaken for a speeding missile: It’s known that an explosion rupturing a fuel tank on a 747’s wing can ignite long streams of fuel, which from the ground may look like a missile heading toward the plane. In addition, U.S. Coast Guard and Navy ships were in sight of every ship and boat in the area and report no firing of missiles or any other pyro- technics. Because of the distances involved and other factors, firing a missile from the ground at flight 200 and hitting it was virtually impossible. Finally, an unsupported allegation—whether from a journalist or anyone else—is not good evidence for anything.