In the comments to an earlier post, some discussion developed regarding whether the halachos of electricity are in the Gemara. Does the Gemara answer the modern question as to whether it is permitted to activate electrical items on Shabbos (I am not talking about electric lights, which is more problematic, but rather other electrical items)?
Various authorities have argued that activating an electrical circuit on Shabbos falls under the Talmudic prohibition of molid (creating something new), boneh (building) makeh bepatish (completing a construction), causing sparks, burning (the fuel), or cooking (the wires). Rav Shlomo Zalman Auerbach, on the other hand, argued that electricity is not comparable to any of these things, and is thus only prohibited due to custom and due to the risk that it may lead someone to switch on an electric light.
Now, I am certainly not going to argue that Rav Shlomo Zalman is definitively correct; I do not even know how one could do so. However, the very fact of the existence of his view sheds light on the situation. Nowhere does the Gemara discuss electricity, because it hadn't been invented yet. Is electricity analogous to other activities described in the Gemara? In some ways, yes, and in other ways, no. So is it sufficiently analogous to the Gemara's activities to be prohibited? That is a matter of dispute between Poskim - i.e., it is a matter of personal judgment. The Gemara itself does not say whether electricity is analogous to these things!