Answers to Quora Questions by Yair Davidiy (22 August 2017, 30 Av, 5777)
Is Jewish people a concept of ethnic or religion? For example, is an ethnical non-Jewish people believing in Jewish religion regarded as a Jewish people?
All the other answers that I saw seem correct.
Adherence to the Jewish Religion is the main point.
The Ethnic affiliation in theory should have only marginal significance.
In practice it is very important.
The feeling that one's ancestors came out of Egypt with the other Israelites and received the Torah on Mount Sinai and all the rest is inculcated.
Whether it is historically true or not is not so important.
Nevertheless, it would seem that there really is an inherited component common to most Jews who remain faithful to Judaism.
Jewish tradition strengthens this assumption.
And if in individual cases such may not be the case as who cares?
Judaism says a person is born as they chose to be in accordance to how they would have wanted it to be.