&quot;Strong typing&quot; and &quot;weak typing&quot; don&#x27;t really mean anything:<p><a href="http:&#x2F;&#x2F;blogs.perl.org&#x2F;users&#x2F;ovid&#x2F;2010&#x2F;08&#x2F;what-to-know-before-debating-type-systems.html" rel="nofollow">http:&#x2F;&#x2F;blogs.perl.org&#x2F;users&#x2F;ovid&#x2F;2010&#x2F;08&#x2F;what-to-know-before...</a><p>You probably mean &quot;static typing&quot; versus &quot;dynamic typing&quot; which I wrote a bit about in the context of Julia here:<p><a href="http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;28078089&#x2F;is-julia-dynamically-typed" rel="nofollow">http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;28078089&#x2F;is-julia-dynamic...</a><p>Basically, I think &quot;type stability&quot; hasn&#x27;t really been a thing in the past because in dynamic languages, people have traditionally not cared about ensuring that return types are predictable based on argument types, and in static languages, a program is <i>incorrect</i> if that&#x27;s not the case. As people care more and more about being able to statically predict the behavior of programs in dynamic languages, the concept of type-stability in dynamic languages becomes increasingly important.