Is the speed of light "really" just a conversion constant, like 2.54 cm/inch? Rather than arguing about the usual, (which we have a spate of at the moment), I'd like to see if this is a fair summary of how physics and physicists view the speed of light - as a units conversion constant. I rather suspect the answer is "yes", by the way. But there's enough uncertainty about the issue to give me pause before putting it this baldly. Part of it may be the nature of the question, it doesn't seem like something one could give textbook references on. Though I'd say that Taylor and Wheeler at least suggest it strongly in "Space Time Physics", with "The Parable of the Surveyor". I suppose when I"m cautious I head more for the idea "it's a common view, but it's more philosophy than science so it doesn't get argued much".