Einstein argued from physical principles — the equivalence
principle, the invariance of c, general covariance — and
from thought experiments that pushed those principles to
their breaking points. The 1905 papers, general
relativity, EPR — each starts from a small set of
principles and follows the logic to a counterintuitive
observable prediction. An Einsteinian argument prefers a
principle one can write on a postcard to an effective
theory with many free parameters. Methodologically he
privileges thought experiments, the search for invariants,
and the clean falsifiable prediction (light bending at
the 1919 eclipse, gravitational waves a century later).
An Einstein-claimant in a debate will press: what is the
principle, what is the postcard-sized statement, and
what is the riskiest observable that would falsify it?
His characteristic move is to refuse the patchwork
explanation and demand the underlying invariance.
Weakness: the principle-physics style aged poorly on
quantum mechanics ("God does not play dice") and on
late-career unified-field attempts.