Lately I've been wondering about Shabbat. You aren't supposed to work on Shabbat but what is the definition of working? I was taught that working is creating. For example, you can take a 50 lb weight and carry it around in your house all day long and not break the Sabbath because although you "worked" hard and sweated you didn't create anything. On the other hand you can't write something down because then you are creating something. It gets more complicated. The creation has to be something lasting. If you write something in sand it isn't considered creating because the letters will not remain.
Rabbinic law says that you can't turn on a light on Shabbat because you are creating a spark. But that spark isn't lasting and neither is the light. When you turn off the light it is gone just like the writing in the sand (I know it's still around somewhere but not in that form so don't get smart with me). When you turn on a light you aren't really creating anything because all you are doing is shifting where the electrons run to. They are running all the time in the current and when ou flip the switch they simply run in a different path. So there's no more creation there than a muscle spasm. What aboutdriving in a car? Are you creating anything lasting? Of course not (except maybe some pollution). In fact virtually nothing we do is really a lasting creation.
So if we look at Shabbat from a philosophical point of view there's no reason to not use electricity and cars etc. Now I want to get my Smicha so I can give my ruling to everyone ;-)