Turning to semantics, while all six translations have family resemblances to one another, philosophically the ontological claims made in 1, 2, 4 and 6 are different from 3 and 5 with respect to the nature of the dao: in the former, if you can talk about it, it isn’t a (or the) unchanging dao; whereas in 3 and 5 the claim is that if you can walk (tread, follow) the (or a) dao it isn’t a (or the) unchanging dao. The articles in parentheses are also of ontological import here: “a” dao is surely different from “the” dao (there are no articles in Chinese). Four of the translators had “way”/“tao”/“dao” grow capital letters, presumably to tell the reader something more than would be conveyed by using lower case (impossible in the original, of course). But what exactly is it that is being conveyed?