Should User Interface Designers Know Code?

I love the first paragraph of this answer to the question Should user interface designers be able to build what they design? on Quora:

UI literally ‘interfaces’ between two things: software code and the human eye/brain. The whole purpose of UI is to connect code on one side and human senses on the other. So I don’t think it makes sense to call oneself an interface designer unless there is at least an understanding of how programs work, how databases work, and so on. Otherwise what is the design interfacing to?

Ryan Singer

I feel this acutely in my 9–5 as we design and build all manner of pages, applications, systems and physical objects for thousands of people to interact with. It all comes down to people. And I’m not talking about people interfacing with things as a design problem to be solved—thanks to situational experience and the leadership I’m under, I’m beginning to see it more as a gift to be stewarded.

My team and I are designing and building solutions to bridge the gap between people and software, or people and information. We’re removing barriers, adding increasing clarity and appropriate context to these interactions. How can we possibly do that well if we don’t understand both sides of the interaction? How can I possibly design clear, appropriate user interfaces if I don’t have at least a cursory competent understanding of what I’m building this bridge between?

If we use the Dreyfus model of skill acquisition as a gauge, I don’t think code competency (some perception of actions in relation to goals, deliberate planning, formulates routines, etc.) is too much to ask for from a UI designer.