It is one thing to know that each planet periodically reverses the direction of its motion with respect to the background of fixed stars; it is quite a different matter to know why.
3)[1] According to the National Research Council (United States): "Scientific inquiry refers to the diverse ways in which scientists study the natural world and propose explanations based on the evidence derived from their work.
"[2] The classical model of scientific inquiry derives from Aristotle,[3] who distinguished the forms of approximate and exact reasoning, set out the threefold scheme of abductive, deductive, and inductive inference, and also treated the compound forms such as reasoning by analogy.
In this classification, a deductive-nomological (D-N) explanation of an occurrence is a valid deduction whose conclusion states that the outcome to be explained did in fact occur.
Depending on a number of additional qualifications, an explanation may be ranked on a scale from potential to true.
[1] During the course of history, one theory has succeeded another, and some have suggested further work while others have seemed content just to explain the phenomena.
[5] A good theory: Stephen Hawking supported items 1, 2 and 4, but did not mention fruitfulness.
Nonetheless, these criteria contain subjective elements, and are heuristics rather than part of scientific method.
It also is debatable whether existing scientific theories satisfy all these criteria, which may represent goals not yet achieved.
[10] Whatever might be the ultimate goals of some scientists, science, as it is currently practiced, depends on multiple overlapping descriptions of the world, each of which has a domain of applicability.
Occam's razor might fall under the heading of "elegance", the first item on the list, but too zealous an application was cautioned by Albert Einstein: "Everything should be made as simple as possible, but no simpler.
"Those among us who are unwilling to expose their ideas to the hazard of refutation do not take part in the game of science."
[17] As an example, Kuhn suggested that the heliocentric "Copernican Revolution" replaced the geocentric views of Ptolemy not because of empirical failures, but because of a new "paradigm" that exerted control over what scientists felt to be the more fruitful way to pursue their goals.
Because of these interesting characteristics of formal systems, Bertrand Russell humorously referred to mathematics as "the field where we don't know what we are talking about, nor whether or not what we say is true".
For example, we could do a simple syllogism such as the following: Notice that it is not possible (assuming all of the trivial qualifying criteria are supplied) to be in Arches and not be in Utah.
Therefore, it is never correct to say that a scientific principle or hypothesis/theory has been "proven" in the rigorous sense of proof used in deductive systems.
Scientists tried everything imaginable to explain the discrepancy, but they could not do so using the objects that would bear on the orbit of Mercury.
Eventually, Einstein developed his theory of general relativity and it explained the orbit of Mercury and all other known observations dealing with gravitation.
Another example of correct scientific reasoning is shown in the current search for the Higgs boson.
However, realizing that the results could possibly be explained as a background fluctuation and not the Higgs boson, they are cautious and waiting for further data from future experiments.
Said Guido Tonelli: "We cannot exclude the presence of the Standard Model Higgs between 115 and 127 GeV because of a modest excess of events in this mass region that appears, quite consistently, in five independent channels [...] As of today what we see is consistent either with a background fluctuation or with the presence of the boson.
Argument from analogy is an unreliable method of reasoning that can lead to erroneous conclusions, and thus cannot be used to establish scientific facts.