One of the points he makes is that science talks only about relational properties and doesn't discuss intrinsic properties.
[Physics] does not, and cannot, tell us anything about the natures of the entities that enter into these relations – nothing over and above the relations they enter into. Any entities we identify are simply place-holders for further relations, and are analysable as a nexus of relations.Rowlands does have a point, but I'd like to investigate his notion of intrinsic properties further.
However, intuitively, not certainly by any means, but this is the way we tend to think about things – reality contains more than just relations. When things enter into relations, they do so because of the natures of the things that are related. Relations are ontologically dependent on things, and things have natures that explain the relations those things enter into. I don’t know: maybe it is all relations – but that is another thing that would surprise me; and if scientism is based on that premise, maybe it’s best to bring it out into the open, because I suspect that it is indefensible (independently of a discredited form of verificationism).
In science, there are two kinds of properties: purely relational properties, such as position, momentum and wavelength, and "pseudo-intrinsic" properties, such as rest mass, charge and spin. I call the latter "intrinsic" properties because we can reduce a lot of relations to a particular set of irreducible properties that are the same in all frames of reference. They are "pseudo-intrinsic" because they can always be restated as a set of relations: The rest mass, charge and spin of an electron are just another way of talking about how electrons relate to (among other things) electric and magnetic fields (and the pseudo-intrinsic properties of the fields are just another way of talking about how electrons relate to the fields).
I think Rowlands is being fair in saying that science talks only about relational properties, that is just those properties that can, in principle, always be restated as relations. To state these properties as "intrinsic" is more convenient, but it's definitely the case that it's not logically necessary to do so.
The question for Rowlands then is whether our intuitions about intrinsic properties just refer to these pseudo-intrinsic properties. (If so, then discourse about intrinsic properties is just discourse about pseudo-intrinsic properties, and thus fully commensurate with science, and does not require a method other than science.) If not, are we justified in taking our intuitions about truly intrinsic properties as veridical or are these intuitions merely mistaken?