# If the only two empirical measurements we can make are change in length and passage of time, how are dimensions and units of quantities formulated?

So this is something really confusing to me. Recently a professor of mine gave a talk and said something that I thought was very interesting and kind of crazy. "The only two quantitative measurements we can make are, changes in length - in multiple dimensions - and passage of time. With these two different forms of measurement people have come up with all of Physics."

At first I was not convinced and the first thing that came to mind was mass and maybe electric/magnetic quantities, but then when I looked at how we measure them, it is indeed just a change in length on some scale and passage of time. So how did the formulations of dimensions and units come about?