We routinely feel emotional about materials — often subliminally. Which is why new substances and techniques for manufacturing have provoked vivid writing, particularly during the design-reform debates of the 19th century. Think of John Ruskin on the evils of cut as opposed to blown glass or his views on wrought iron as opposed to cast iron — the latter emblematic in his view of a ‘sophisticated, unkind, uncomfortable, unprincipled society’.