> but the opening bit has always seemed straightforward to me

the a/symmetry of the opening bits in Chinese, visually echoes a taiji:

> 道可道，

> 非恆道；

> 名可名，

> 非恆名。

given the diversity of translations available for those bits, I think it's fair to say that there's room for debate regarding their exact meaning − dare I say

amusingly, by being certain one understand what it means, somehow one really does not. Lao-Tseu may have been way, way wiser than average.