VIJAI:
"If it is not, how come the (immutable) laws of nature are little known or understood...."
What do you mean by "immutable laws of nature"?
Scientific principles are discovered and interpreted by humans.
This is limited by the data we have to work with at any one point in time - and as such scientific knowledge continues to be added to all the time.
This has led to the modification or replacement of many seemingly "immutable" laws of nature.
For example the geocentric model for the solar system was long held to be an "immutable" law until it was replaced by heliocentrism which in turn became modified when it was proved that the sun was a star and that most stars had solar systems of their own.
Likewise the Newtonian theory of gravitics was itself modified by the Einsteinian model.
Science is never "immutable" - as I said it is dependant on the data we have to work with.
This is why science is always considered provisional.
It is in turn significant when theories like gravitation and evolution remain essentially correct today except for modifications and expansions.
VIJAI:
"...and the strict methods of correct reasoning are very seldom observed?"
I agree that correct reasoning is sometimes not observed in science.
However the self-correcting nature of science and scientific discovery is that mistakes, hoaxes, poor reasoning, and poor science are ALWAYS discovered in the long run.
In fact in the modern world, such is the dissemination and cross-pollination of scientific research among different branches of science that this self-correctional function has only improved and quickened as the pool of criticism and discussion becomes wider and more astute in observation and correction.