Something I encountered recently changed my outlook on &quot;the speed of light&quot;..<p>The &quot;speed of light&quot; is not really the speed of light - it&#x27;s the speed of causality.<p>When one measures the &quot;speed of light&quot;, one is measuring the time taken between two events;<p>Event 1 : the moment a beam of light was emitted from a location.<p>Event 2 : the moment that beam of light was detected at some other location.<p>The time taken for light to traverse between its initial emission and its subsequent detection, is basically the speed of causality.<p>For me that was a bit of an epiphany, and makes it much easier for me to understand the concept of spacetime that previously had me befuddled.<p>Also, the realisation that the &quot;speed of light&quot; is denoted as c (causality, anyone? ;) ) made me smile :)