Inside the Room: How Mentors Think, Challenge, and Decide

For many technical founders, the biggest risk is a blind spot, one they cannot see because it is their own. It is precisely here that the mentors' way of thinking begins.  

Olivier Perquel, a former investment banker who mentors founders at the Creative Destruction Lab (CDL), a deep tech accelerator, describes the approach as a "structured mentoring exercise." In each stream of the CDL program, roughly 20 to 30 experts bring their experience to the table. The operative word is collectively. Mentors do not reason as a series of isolated advisors, each delivering a separate verdict; they reason as a group.

Diversity gives the room its strength. A Nobel Prize winner, a serial entrepreneur and a top-tier venture capitalist each look at the same venture from a different angle. When they debate a single strategic objective together, their perspectives combine into a collective mirror that reflects the venture from several sides at once. This shared reflection brings the founder's blind spots into view. As Olivier Perquel notes, the group helps founders "figure out what there is no way they could know" on their own. 

Each mentor brings decades spent in the trenches, along with the "scars" that come with them. These lessons circulate quickly during the sessions, giving founders advice grounded in what mentors have experienced firsthand. 

How Mentors Challenge: The Power of Smart Questions 

In the room, feedback can be "harsh" or "direct". It works like a scalpel: every cut is precise but meant to heal. Renaud Visage, co-founder of Eventbrite and a Climate mentor at CDL, notes that, of course, deep tech founders walk in with their science already mastered. Mentors bring something else: “smart questions” that sweep across a startup’s reasoning and catch the cracks in its logic.

This questioning is the core instrument of the mentors’ method. Mentors focus on the reasoning that must carry the science to market. Faced with a founder’s plan, they identify the recurring patterns they have seen work or fail and bring them to the surface.  

Identifying these patterns turns mentors into “obstacle removers.” They help founders navigate the “zillions of regulations” or the complexities of manufacturing at scale. Asked at the right time, a smart question becomes the fastest way to the market. Seen in this light, the challenge serves the founder’s ambition: it anchors that ambition in “truth and data” and carries it beyond pure aspiration. 

The challenge, however, does not depend on mentors alone. Ultimately, the pivotal moment in the room rests with the founder. Everything hinges on one shift: from being defensive to being “coachable.” Founders such as Adnane Lahbabi of AlphaGuard describe how mentors guided them from a vague idea toward a defensible “operating system” narrative, a progression shaped by a constant “back and forth” of hard feedback. 

Deciding: Setting Priorities to Focus 

This back-and-forth unfolds within a demanding format: a structured, recurring format that organizes the founders’ work over several months. 

By the fourth session, the relationship between founders and mentors has undergone a qualitative change. What began as an exercise in tough constructive feedback has matured into a bond. Each session concludes with three priorities rather than an extensive list of tasks. The difference lies less in the number of items than in the logic behind them. A list grows by accumulation, whereas prioritization requires founders to select among competing options. 

The method favours subtraction over prescription: it strips away the superfluous until only the essential remains. Therein lies a deeper purpose: for a young venture, speed comes from doing fewer things and focusing harder on them. Making a decision means choosing what to drop, and the few remaining priorities that are left show the startup the way forward, so it can move faster and give itself the best chance of success.

Watch the video: CDL-Paris Mentorship and Student Awards 2026