The deductive method in science seems to be the in-thing these days. We do science to understand the real world, and the empirical scientific method is the best way to do that. Some scientists, however, believe that truth is found through rational thought. They use a presumed law of nature that's generally accepted about how things work. They work out, that is, deduce its logical consequences.
When the deductive method is used on a hypothesis, IF enough experts in the field accept the result, the hypothesis gets promoted to theory status.
The deductive method is an example of the Greek philosopher Socrates' ‘dialectic’ method. It's the art of investigating or discussing the truth of opinions. Socrates taught that truth is uncovered through conversations with informed people. In other words, the correctness of a hypothesis is determined by expert consensus, by a vote.
Today's peer review mechanism makes deduced theories more important than experimental results. Submitted articles to scientific publications must be reviewed and approved by fellow scientists.
Peer review committees review and accept research proposals before funding is given. Some institutions have internal review committees that scrutinize proposed papers before being sent to external journals. It's the Socratic method in full flow.
Peer reviewing cuts out "what if" submissions. That's a good thing. Unfortunately, anonymous self-interested reviewers may prevent legitimate alternative, competing proposals from getting into the limelight. Reviewers often reject proposals because they don't conform to established "beliefs." Perhaps peer reviews ought to be called competition reviews.
Applicants have no say in who does the reviewing. Today's peer review system in astroscience has sunk to the level of censorship and suppression, especially when established paradigms are questioned.
Ultimately, proposals that challenge accepted scientific dogma will never see the light of day.
It gets worse. The peer review system often accepts for publication pseudoscientific results that agree with current dogma without questioning whether the empirical scientific method has been used! That's terrible science.
Peer reviews work great in disciplines where wrong ideas are easily falsified, such as in engineering and chemistry. But in astroscience, where experimentation is often difficult, peer reviews may prevent progress. They are used today to maintain accepted paradigms.
A Deductive Method Flaw
A major flaw with the deductive method approach is that once a theory becomes accepted, it;s difficult to reject later on if conflicting evidence arises. When that happens, the theory tends to be modified - made more complicated - to accommodate the new data.
Such theories then tend to become fixed, with any finer points simply debated and added. Unfortunately, the frameworks of such deduced theories tend become permanent.
Another Deductive Method Flaw
Another big flaw of the deductive method is that if the original presumptions turn out to be wrong, it becomes rather difficult to go back to square one and begin anew. That's because by then, there'll be publications, books, and other writings and teachings that will have to be scrapped!
Think about that. Who wants to re-learn things that are taken as facts? It's not the done thing today. However, it's poor science NOT to do so because truth cannot be hidden - it ALWAYS emerges.
Experience defeats arguments every time. When experimental evidence clearly shows that ingrained theories have been wrong all along, we MUST go back to the drawing board and re-learn. That's easier said than done. Who wants to call in and trash, and then rewrite established textbooks? Who wants to revise educational curricula? Is that affordable?
To avoid these difficulties occurring, one would think that the priority is the empirical method in science. The deductive method should be used as a backup to derive testable consequences. However, by inverting these priorities, as is common in astroscience, we risk creating a pseudo-religion. That's because, in religion, revelations of truth override observations and facts.
Indeed, in the sciences that deal with events that supposedly happened long ago or far away, in which the deductive method reigns, theory overrides empirical facts. If the facts don't fit the theory, they have to be changed!
Oh, dear. Such nonsense leads to falsehoods.
Only the repeated use of the empirical method can reveal truth and reality. Not doing so and placing deductive assumptions out of the range of testability is easy to do. It makes deductive theoreticians famous. However, then all sense of reality is lost.
Example: Nuclear Fusion
Controlled nuclear fusion technology was once thought to be the answer to our electricity generation problems. Using deuterium from seawater as fuel, we would have thousands of years of pollution-free energy. It sounds good.
But why hasn't controlled fusion energy become a reality? Because many of the conclusions that came from plasma theory were wrong.
A scientific theory is valuable only when it's developed in contact with reality. Without experimentation to bolster arguments, we go down the road to fantastic places like Lewis Carroll's "Wonderland" or Tolkien's "Middle Earth."
As Roger Bacon said: "Experiment is that which alone, as the mistress of speculative science, can discover truths in the fields of other sciences, to which these other sciences cannot attain."
So now you know.