Many who belonged to the empiricist consensus held that, at least ideally,
lower level theoretical statements (whether regarded as mere "hypotheses"
or as "laws") could be explained by showing that they could be validly
from higher level more embracing theoretical statements, until in an ideal
perfected science, all phenomena could be seen as deducible from set of
relatively few fundamental "laws of nature." The epistemic justification
for such theoretical laws, then, is seen as based upon the "foundation"
of all actual observation statements which confirm the predictions
deduced from the theory; this foundation "supports" or "rationally justifies"
the theoretical structure of scientific laws which is erected upon it.
Hence this view is said to be a form of "foundationalistic epistemology."
One could imagine that in an ideal case the body of rationally justified
scientific beliefs, a "total unified science" could be arranged as a hierarchy
of statements with the most general all embracing fundamental laws
of nature at the top and lower level, more specific laws being deduced
from them under restricted conditions, in much the same fashion that the
theorems of geometry follow from its fundamental axioms and postulates.
However, such a system of deductively interrelated theoretical statements,
becomes "science" only because the rational warrant for belief in these
statements comes not from the "top down," i.e., from axioms to theorems
(as appears to be the case in geometry), but from the "bottom up," i.e.,
from the empirical observation statements which serve to confirm
directly the lowest level most particular statements deduced from the
system of theoretical laws.