THE SCIENTIFIC METHOD
The scientific method is a methodology one (supposedly) uses in pursuit of scientific truth. The elements are known to most of us:
1) Hypothesis--Offer a concept or idea of how data might best be interpreted. For example, why do the sun, moon, stars and planets move around the earth as they do, with the planets exhibiting "retrograde motion," that is, appearing to move backward in the sky?
2) Test against data. In science, the data is "future" data. That is, a testable / repeatable experiment is performed, and from which data can be derrived. For example, the planet Jupiter will keep moving, and therefore, one can test the competing theories of Ptolomy and Copernicus to predict the future position of the Jupiter.
3) The theory that answers the most data is preferred; and
4) The theory that is the simplest and most elegant is preferred over ugly and combersome theories.
Elements 3 and 4 do not always line up. For example, Ptolmey's explanation of retrograde motion (why planets appear to move backwards relative to the stars) at certain seasons was that the sun, moon, stars, and planets rotated on spheres controlled by various "epicycles." (Picture a child's gyroscope within a second gyroscope, within another gyroscope, to about 45 or so levels, each gyroscope driven by a complex movement of gears like a swiss watch. Though neither of these pictures exacly describes an "epicycle" of Ptolomy, they are as close as we will come here.)
Copernicus offered an alternative hypothesis, that the larger a mass was, the more stationary it was, and that therefore, with little measurable error, the earth rotated around the sun, and revolved on an axis.
Amazingly, it was not until the time of roughly Abraham Lincoln that measurements were exact enough that the Copernican theory could better predict data . . . where the planets would be found. Nevertheless, because it was so much simpler and more elegant than the Ptolemiac theory, it had become the favored theory centuries before Abraham Lincon's time.
The dominance of the Copernican theory prior to experimental superiority therefore highlights the importance of the simplicity or elegance of a theory. If a theory becomes unwieldly, complex or convoluted, it must give way to a simpler and more elegant theory.
THE METHODOLOGY OF THE LAW
The scientific method is not unique to science. It is fundamently the same method used in criminal law.
In a court of law, the defense attorney and the prosecuting attorney each have different perspectives through which they view the case. These are equivalent to competing scientific theories.
And both theories are weighted against a body of data known as evidence. The prosecuting attorney attempts to demonstrate to the jury from the evidence that a person is gulity of a certain crime. The defense attorney seeks to demonstrate from the same body of evidence why her client is not guilty. The jury is left to weigh the evidence.
It is the duty of the jury to weigh the competing theories, considering both the amount of evidence answered by each competing theory, the significance of each piece of evidence.
But as with science, the jury will also weigh the reasonableness of the explanation given to that evidence by each of the attorneys. Which theory answers the evidence most elegantly or simply? The defense attorney can offer a very elaborate explanation as to why there was no murder weapon at the crime scene if the victim committed suicide. He may even offer an convoluted tale as to how she might have continued to club herself when autopsy reports show she was dead of carbon monoxide poisoning before she was struck wtih a club. But no jury is likely to accept an unwieldly, convoluted explanation when a simple and rational explanation is at hand..
The methodology of the court room, therefore, is essentially the scientific method. The only real distinction between law and science is that science appeals to a body of evidence that can be repeated. For example, the planet Jupiter will move to a new measurable location tomorrow or next month. So competing theories can be tested against future evidence. In law, the fundamental body of evidence is not repeatable. Mrs. Smith will never be killed again, so the data from the past is fundamentally the only data that one can used.
Secondary evidence may be scientific. For example, a scientist may testify that, in view of the amount of carbon monoxide in her blood, Mrs. Smith was dead before she was bludgened to death. The absorbtion of carbonmonixide by a person, and the level at which it becomes leathle, can be repeated experimentally. Testable/repeatable experiments may be used to interpret the facts surrounding Mrs. Smith's death. But the actual death of Mrs. Smith can never be repeated.