Scott Swain on Trinity without Hierarchy

I’m reading through parts of Christian Dogmatics, in particular, Scott Swain’s essay on the “Divine Trinity,” where he notes:

The Father is the fontal source of the Son and the Spirit, and these relations manifest his distinct personal perfection. However, the Father’s identity as fontal source of the Son and the Spirit is not (even logically) prior to the existence of the Son and the Spirit but is rather constituted by his eternal relations to the Son and the Spirit … For this reason, we cannot ascribe any priority to the Father in relation to the Son and the Spirit in terms of either being or hierarchy (pp. 99-100).