&gt; A more ambitious example: imagine the web with JavaScript replaced by Haskell. Your code compiles and typechecks in your browser, but that doesn&#x27;t guarantee that it will do the same in mine, or a different version of yours, or tomorrow&#x27;s new browser. So these static type guarantees are very weak because they only apply to a single runtime environment.<p>Wait... What? Are you saying that natural numbers in South America in 1990 century is different from natural numbers in Europe 2010? So how can types be different depending on browsers?<p>Of course, if the browser implements a &quot;compiler&quot; that doesn&#x27;t follow the basic principles reported in the standard of the language, it&#x27;ll happen. If some joker wants to call `Int` a `String`, problems will happen. Otherwise, it is not true.