Scientific Theories And Laws

When I was younger, I was under the impression that scientific "theories" become scientific "laws" after passing a certain evidential threshold, the evidence being gathered by repeat observations and testing.  Sometimes I hear people express a similar belief.  However, this is only partially correct.  This is an inaccurate understanding of both what a scientific theory and law are, and an accurate understanding of both is vital to comprehending the nature of science and the scientific method.

In actuality, a scientific law is a description that matches most or all recorded observations of phenomena in the physical universe, and a scientific theory is an explanation, current or outdated, for why that law holds.  The theories change from time to time even if what is considered a law remains far more static.  A law could remain unchallenged for decades or longer even as the affiliated theory/theories shift and depart, revised or discarded to better fit past or new data.

Scientific laws are identified through repeat observation, just as scientific theories are formed on the basis of repeat observation.  However, theories are not laws in their embryonic stages.  Theories don't and can't become laws; they attempt to explain them.  This is a crucial difference.  The two are always distinct, despite being related very intimately.

Now, there are some truths about scientific laws that aren't often acknowledged.  There isn't a single scientific law that is either true by necessity--any scientific law could have been different and could change in the future--or demonstrably universal.  The latter means that unless I am perceiving the entirety of the cosmos, I cannot know if the decay of matter, for example, is uniform across all of the material world, or if heat melts ice elsewhere in the cosmos.  Since I can only perceive a very small amount of the external world at once, I cannot make any legitimate claims about how matter operates outside of my perceptions.  A being like myself can only intake a very limited amount of sensory data at once, all of which pertains to a relatively small area.

A right understanding of scientific laws and the theories that can accompany them is necessary to a sound grasp of the nature and scope of what science can reveal about the natural world.  Thankfully, common misconceptions about theories becoming laws are easily corrected, as are many other myths related to science.