Naturally this has already been extensively covered by tvtropes, I present the &quot;Mohs Scale of Science Fiction Hardness&quot; [0]<p>The author makes some good points about particular types of errors. I would not, however, call them shibboleths, that word generally refers to something quite specific and seemingly arbitrary that an in-group uses to identify itself to others in the know. Also, the idea that sci-fi is not actually sci-fi unless it&#x27;s hard sci-fi reeks of No True Scotsman. Some of the author&#x27;s examples were far more egregious than others; I would argue that violating conservation of energy and&#x2F;or momentum is fundamentally and entirely different to a particular choice of society or political system such as a Megacorporation or Empire, In Space!<p>[0]: <a href="http:&#x2F;&#x2F;tvtropes.org&#x2F;pmwiki&#x2F;pmwiki.php&#x2F;Main&#x2F;MohsScaleOfScienceFictionHardness" rel="nofollow">http:&#x2F;&#x2F;tvtropes.org&#x2F;pmwiki&#x2F;pmwiki.php&#x2F;Main&#x2F;MohsScaleOfScienc...</a>