Forty years ago, Marshall McLuhan coined the phrase “the medium is the message”. His thesis was we had become so obsessed with the content of media that we had become blind to its impact on our lives, on the way we behave, the way we think and how we learn.

He was talking about information and communications technologies, of which television had at that time become both powerful and insidious in transforming social lives and relationships.

He would have been gratified to see how dramatically his thesis has been realised in the third millennium. Technology has introduced us to media devices so powerfully compact they have found a new use for the human thumb. With minimal investment of time or kinetic energy, it has become possible for students to pull text, sound or moving images from the ether while ostensibly listening to the teacher.

Wondrous and addictive as modern media are, they still compete with older information technologies which have shaped our knowing and believing. The telescope, for example, gave us the ability to travel intellectually so far beyond ourselves and taught us the humble place we inhabit among the universes. The microscope gave access to an inner world infinitesimally small but enabled us to harness its atomic power to destroy cities.

These, among other legacies, continue progressively to reframe our understanding of our world and of ourselves, bringing in their wake an undermining of belief systems and a shattering of inert ideas.

History since Socrates and the continuing immolation of heretics to the present day reminds us that possession and transmission of information is dangerous.

Books can be a technology so subversive that even today they are burned or banned by court injunction. In schools in the Middle East, staff are employed to go laboriously through every textbook, blacking out words and images that refer to pigs, churches and countries whose existence is denied. Is this more or less absurd than the banning of teaching evolution in the United States? Or the debate in third millennium Britain over a parliamentary clause designed to prevent discussion of human sexualities?

Information is a dangerous thing, at least in the wrong hands.

However, in this aptly termed information age it is impossible to contain or inhibit the flow of information. By some miracle too intricate to explain, information is floating in cyberspace and can be captured in an instant by simply asking Jeeves (or any other internet search engine), the modern equivalent of the Roman slave who escorted children to the place of learning.

Unlike P. G. Wodehouse’s character, the Jeeves of technology does not mediate or manipulate information, nor stand in judgment, but clumsily retrieves it. It is this lack of discrimination that is seen as the contemporary threat. Without mediation that turns information to knowledge and knowledge to wisdom, people are prey to the most strident, the most seductive or the most powerful of voices.

The mediation of learning is now of central concern in a world in which education is too big to be contained by schooling alone. Herein lies the most immediate challenge to school leadership.

The task is to confront schools’ obsession with the what at the expense of the how. Measures of pupil performance care little about the process as long as the outcome is measurable. Pressure of time to cover the syllabus makes pupils impatient with distracting conversations about the nature, source or style of their learning. The end justifies the means.

The anachronism of the pen and paper exam, downloading information in quick time in a hall, is out of tune with an age in which information and intelligence reside less and less inside individual heads. Intelligence as well as information lies in between people and in the smartness of the technologies they engage with. The proliferation of new ways of learning and the extension of contexts of engagement demand that we give thought to the how of learning and the way in which it drives and sustains the what.

Of what is learned in those concentrated years between 5 and 18, a fraction carries forward into life after school. For most, much of it remains in disembodied soundbites, occasionally retrieved from a repertoire of curious facts, untheorised, taken as read. So young people emerge from schools neither knowledgeable nor expert with the technology of their own learning.

The task is to make visible the how of learning, by conversations and demonstrations about pupil learning, professional learning and organisational (or systems) learning. School leadership should nurture the dialogue, extend the practice and help to make transparent ways in which these three levels interconnect. It should demonstrate neither a Luddite antagonism to ICT, nor an evangelical embrace. It should promote a continuing restless inquiry into what works best, when, where, for whom and with what outcome. Its vision is of the intelligent school and its practice intersects with the wider world of learning.

If the Government’s latest big idea, personalised learning, is not to remain a vacuous mantra, it will require leadership which does not chase the latest fad or add another bright idea into an already tired curriculum.

We need leadership which fosters a critical and confident understanding of what knowledge is of most worth, and the many routes to its acquisition.

Professor John MacBeath is chair of educational leadership at the University of Cambridge

SETT National Priorities: New Wine, Old Bottles? Wednesday, 12.15pm