The question of “the role of technology in teaching” is a staple issue in educational research and reform. But it shouldn’t be, because it is a very backwards way of looking at things.
Consider an analogy: “the role of words that begin with the letter S in poetry.” Suppose there was an industry of scholars devoted to “researching” whether words that begin with S are effective, and suppose that every aspiring poet was asked for his stance on the role of words that begin with the letter S.
Of course poets are not so stupid as to engage in such madness. They know that you chose the words that best fit what you have to say, regardless of what their initial letter happens to be. Sometimes you end up with plenty of words that begin with the letter S, sometimes not. It doesn’t matter. The important thing is content, the point is what you have to say, not incidental matters of presentation.
It ought to be the same in teaching. You do not start by asking how you can use technology in your teaching, just as a poet does not start by asking what he could say with words that begin with S. You start by considering what you want to say. Then you choose the form of expression most suitable thereto. That is how poets do it, and it is how teachers should do it too. But, as the nonsensical fixation on “the role of technology in teaching” shows, mathematics education researchers and reformers are incapable of such level-headedness. Once again they err because they are too focussed on surface form as opposed to substance, just as I argued in the Manifesto.