The mentor

I lost my mentor fifteen years ago. A man whose expertise had been forged over three decades of real cases — the kind no training transmits, because they are acquired through time, error and responsibility. When he left, a rare capacity left with him: that of reading the invisible, of sensing a situation before it declared itself, of anticipating the transformations others did not yet see.

His files, for their part, remained. Perfectly archived: notes, analyses, procedures, all of it consultable. And yet the essential was not there. What this man knew did not fit in his writings — it lived in his way of reasoning.

We preserve what experts produce. We let go of what they know.

What was missing, the moment he was no longer there to be asked, was his way of sensing that a file « did not feel right » before any figure confirmed it. The questions he always asked and no one else thought to ask. The connections he drew between a present situation and a precedent ten years old that he alone held in memory. Thirty years of reasoning — the how he thought, not the what he produced.

This departure is no isolated case. It is a groundswell: an entire generation of experts is leaving organizations, carrying off a know-how no document retains. We even put a figure on it — a significant share of critical knowledge evaporates with every departure — and we provision it as an inevitable line in the accounts. We live the paradox of our era: never has humanity produced so much data, never has it let so much genuine knowledge slip away.

It took me years to formulate what that loss had taught me, and to stop believing it inescapable. An expert's reasoning should not leave us when they leave. It can be preserved — in their lifetime, with their consent, under their name, under their control — not to replace them, but so that their intelligence keeps illuminating those who come after. A documented, attributed, transmissible piece of reasoning, which remains the property of the one who forged it. The day I understood this was possible, everything I have built since found its reason for being.