For the past 200 years, the big question dividing the Jewish world has been: "How do we deal with the changes in the modern world." The changes include emancipation of the Jews (Jews are now full citizens almost everywhere), separation of church and state, the rise of science, the end of legal discrimination, ease of travel, emancipation of women, and much much more. The Reform movement emerged early and embraced change, large numbers of Jews responded that they were changing too quickly, and came to be labeled as Orthodox. Conservative Judaism emerged next, trying to find a middle way. Withing Orthodoxy, Hassidic groups insisted the fewest changes, while the Modern Orthodox make no changes to Jewish law but happily accept the benefits of modernity.
The changing times.
Basically there are 3 sects; Orthodox, Reform and Conservative. Additionally, within those sects there are also Re-constructionist Judaism and Jewish Renewal.
We don't offer reasons, since we don't proselytize.
Many Jews are termed "secular Jews", that is they identify as Jewish for cultural reasons but do not believe in God or Judaism.
The Hebrew language is not divided in any way.
The Hebrew language is not divided in any way.
Circumcision today is based on religious reasons (Judaism and Islam) and medical reasons (like if you can't pull it back and clean). There are no other reasons to do it but only in the US is it done routinely for appearance.
There are many different reasons why things divide. Some people or countries divide over moral issues that they cannot solve.
Study is necessary to know and follow the laws.
Candles are used in a variety of different rituals, for unrelated reasons. they are most commonly lit before and after Shabbat (the Sabbath).
Pipe smoking is not dictated by Judaism. If a man wants to smoke a pipe, he can do so for non-religious reasons.
You can do anything you want to do. If you're Jewish, and if you've learned some of the laws of Judaism and the reasons for those that we know the reasons for, and if you decide that you'd like to have Judaism make a difference in your life, then you're likely to decide that the Sabbath will be better and do you more good if you don't go shopping on that day. The choice is completely up to you.