The question is whether the concept of data is essential to how we structure computation.
Computation is a physical process and any model we use to build or describe this process is imposed by us. Whether this model should include the concept of data (and their counterparts "functions") is really the question here. While I don't think the data/function concept is essential to modeling computation, I also have a hard time diverging too far from these ideas because that is all I have seen for decades. I believe Kay is challenging us to explore the space of other concepts that can model computation.
Computation is a physical process and any model we use to build or describe this process is imposed by us. Whether this model should include the concept of data (and their counterparts "functions") is really the question here. While I don't think the data/function concept is essential to modeling computation, I also have a hard time diverging too far from these ideas because that is all I have seen for decades. I believe Kay is challenging us to explore the space of other concepts that can model computation.