Very simple: Try testing: "The laws of science are universally rational and applicable."
Your quote is not a "scientific" truth in the usual sense, that is, it is not itself a law of science, but a statement about the laws of science. The laws themselves must be testable, and cannot be considered laws until they've "passed the test," so-to-speak.
If by "the laws of science" your quote means all those laws thus far discovered and tested, then your quote has been tested by means of testing every law it includes. If by, "the laws of science," your quote means all that have been discovered and proved, and all those not yet discoeverd, and all those still being tested," then your statement is not a truth of science, but a general descriptive concept about science, and does not come under the requrements of a scientific truth itself.
Hank
But any definition of "objective science" offered so far seems to beg the question. More later.
I think that your proposition is both false and engages in question begging.
Interpreting the proposition "the laws of science are universally rational and applicable" poses great perils, both logically and symantically.
It would seem to be along the lines of, for all propositions x, where x is a law of science, x is universally applicable and x is rational.
First, what do we mean by y is a law of science? This would venture far beyond my rather limited knowledge of this subject, but presumably a law, y, must be a proposition that relates variables in sets or classes, say y(E, mc2) is that statement that E=mc2 is a true equation. The proposition does not need to be mathematical, however, to be a "law of science"
I think that the statement "if x is a law of science it is rational" is circular. Generally, the statement x is a law of science is taken to mean that x is falsible, we have tested it, and it has proven true in every "applicable" empirical test to which it has been subject.
Now, let me addresss the universally applicable part. The statement x is a law of science, therefore x is universally applicable is generally false and commits the aesthetic fallacy (assuming something is true because it is beautiful or false because it is ugly). It is a love of physicists, in particular, to want to demonstrate universal truths. The extent to which we have been able to test the laws of general relativity, or the laws of quantum mechanics, applied to the theory of atomic spectra, the laws appear to be universal - i.e. the physical behavior of atoms in distant galaxies appears to be the same as in Berkeley California.
Generally, however, universality is not a property of a scientific proposition. For instance, there are a number of statements that are true about DNA replication in cells at room temperature in a normal atmosphere, that are certainly not true on the surface of Venus. There are statements in biology that are not only not universal, but are complete nonsense extracted from the species that are being described. They are, however, generally accepted laws of science. Most statements in science are accepted as applicable, for some set of circumstances. A scientist generalizes at his own peril.