What we know is you don't know the difference between an 18th century liberal and a 21st century "Liberal".
There is none because both follow the same principles.
Liberal Define Liberal at Dictionary.com
liberal
adjective
1.
favorable to progress or reform, as in political orreligious affairs.
2.
(often initial capital letter) noting or pertaining to apolitical party advocating measures of progressivepolitical reform.
3.
of, pertaining to, based on, or advocating
liberalism, especially the freedom of the individualand governmental guarantees of individual rightsand liberties.
4.
favorable to or in accord with concepts ofmaximum individual freedom possible, especiallyas guaranteed by law and secured bygovernmental protection of civil liberties.
5.
favoring or permitting freedom of action,especially with respect to matters of personalbelief or expression:
a liberal policy toward dissident artists and writers.
6.
of or relating to representational forms ofgovernment rather than aristocracies andmonarchies.
7.
free from prejudice or bigotry; tolerant:
a liberal attitude toward foreigners.