Podcast Summary: "Digital Twins and Virtual Twins: What Are They and What Do They Do for Humans?"

Podcast: Harvard Data Science Review
Episode Date: December 23, 2025
Host(s): Liberty Vittert Capito, Shali Ng
Guests: Rachel Franklin (Executive Director, Center for Geographic Analysis), Patrick Johnson (Head of Corporate Research and Sciences, Dassault Systèmes)

Overview

This episode explores the concept of digital twins and their evolving role in reshaping industries, cities, and society. With expert guests Rachel Franklin and Patrick Johnson, the conversation bridges the technical, social, and ethical dimensions of digital and virtual twins—from their definition to their real-world applications and societal implications.

Key Discussion Points and Insights

1. Defining Digital Twins and Virtual Twins

• Rachel Franklin introduces digital twins as "exact replicas" of systems—whether a jet engine, a heart, or a city—emphasizing the integration of models with vast, often real-time, data feeds.
• Patrick Johnson distinguishes between "digital twin" (a data-rich replica) and "virtual twin" (an imaginative, adaptive model that enables exploration of potential futures, not just copying reality).
  • “With a virtual heart, it can embody not only patient A or patient B, but it can also encompass all kind of pathologies. And we can explore... the realm of all the possibles.” (Patrick Johnson, 04:38)
• Johnson notes the interactive, ongoing relationship between real and virtual: “The twin is a fused representation, let’s say an abstract model plus a real sets of data in a continuous discussion, in a continuous dialogue...” (Patrick Johnson, 05:55)

2. Realistic Applications: Where Digital Twins Move Beyond Hype

• The panel discusses parallels between AI and digital twins: both are sometimes "old wine, new bottles," and both generate both excitement and skepticism.
• Rachel Franklin highlights the journey versus the destination:
  • "It's the journey and not the destination. We recognize a little bit where we would like to be... It tells us when our computing infrastructure isn’t actually fit for purpose at the moment." (Rachel Franklin, 09:45)
• Patrick Johnson contextualizes with Boeing’s design of the 777: “That was the first aircraft that was produced and designed totally virtually... There was almost no errors in the parts definition and the engineering work, which means that the quality of the first 777 was better than the hundredth 767.” (Patrick Johnson, 12:10)
• These technologies are now standard across aerospace, pharma, and urban planning.

3. Current Challenges and Unsolved Problems

• Completeness of Representations:
  • Johnson: “So you put in a twin what you decide to put there. And therefore... what you don’t put into twins translate into non answered questions.” (Patrick Johnson, 15:07)
  • Example: Early digital twins for Boeing’s 787 struggled with new composite materials—modeling physical shape wasn’t enough; new material sciences had to be integrated.
  • “It’s a never-ending journey because the representation needs to be as sophisticated as you go. So the multi simulation, the multi discipline, that’s a high challenge for engineering.” (Patrick Johnson, 17:34)
• Modeling Human Behavior:
  • Franklin observes the gap in modeling genuine human agency in urban systems: “Humans, they’re not agents... my preferences are very hard to identify and they're going to change over time.” (Rachel Franklin, 23:47)
  • Predicting growth, movement, or even fertility rates in cities is laden with uncertainty.

4. Barriers to Adoption: Technical, Institutional, and Human

• Johnson’s main concerns are not technical but about adoption and practitioner buy-in:
  • “What keeps me awake at night is not so much the technical challenges... but it’s the adoption by practitioners and physicians. How are we going to morph the current practice? How are we going to train the next workforce of the future?” (Patrick Johnson, 19:39)
  • Generative AI and black-box models pose reliability/trust issues, especially in regulated industries.
• Franklin points out the need for genuinely collaborative, interdisciplinary teams for effective digital twin projects: “This is not a one person job... there is no such [person] who can do all of the things necessary to actually build, run, test a digital twin...” (Rachel Franklin, 21:50)

5. Ethics, Privacy, and the Value of Data

• Liberty Vittert Capito recounts a personal story about a “smart” bathroom scale that forced her to share personal data with an app, highlighting the modern dilemma of privacy (25:07).
• Johnson shares Dassault’s strict approach to informed consent, traceability, and privacy-enhancing technology:
  • “It all starts with a patient consent... it’s always for specific usage, for a specific purpose, in a specific setting at a specific time.” (Patrick Johnson, 27:01)
  • The concept extends across all industrial and personal data, with strict IP lifecycle management and traceability.
• Franklin is more skeptical about the extent and incentive structures for data use outside health:
  • “Every time you use a credit card, they know exactly how much you spend. And from that they can estimate how much you make... and they know exactly where you’re doing this. And... they know what you’re spending your money on.” (Rachel Franklin, 31:07)
  • She urges reflection on whether investing in massive digital infrastructures is always the most effective route to social well-being.

Notable Excerpt:

• “The product is you.” (Patrick Johnson, 32:34)
• “Yeah, the product is us. And they're making money off of it.” (Rachel Franklin, 32:35)

6. Final Reflections: The Magic Wand Question

At the episode’s close, Liberty poses the “magic wand” scenario:

Rachel Franklin:

• Wishes for “public buy in”—not just societal, but specifically government commitment and public ownership of digital twin infrastructure and data. (36:18)

Patrick Johnson:

• Personal wish: To see digital and virtual twins widely used for enhancing the lives of the elderly—adapting homes, improving quality of life, and connecting families. (36:30)

Liberty Vittert Capito:

• Lightheartedly: A digital twin that could “do many things” for her so she could “go fishing, drinking wine, and talking to you guys instead of jumping from one Zoom to another.” (37:06)

Timestamps for Key Segments

| Segment | Timestamp | |----------------------------------------|--------------| | Defining Digital & Virtual Twins | 01:41–07:19 | | Realistic Applications & Hype Debate | 07:19–14:37 | | Technical Challenges Unpacked | 14:37–17:53 | | Barriers to Adoption | 17:53–21:37 | | Human Behavior & Modeling Limits | 21:37–25:07 | | Ethics, Privacy, and Value of Data | 25:07–35:47 | | Magic Wand Reflections / Closing | 35:47–37:06 |

Memorable Quotes

• "We don't want to do just a digital photograph... we want to use the power of imagination and the power of possible worlds." (Patrick Johnson, 04:23)
• “It's that real-time data and it's the systems approach that I think makes us consider something a digital twin.” (Rachel Franklin, 03:38)
• “People look at twins like it’s a virtual photograph of an object. It’s a management system.” (Patrick Johnson, 13:36)
• “The challenge is… an interesting and fun and worthwhile one.” (Rachel Franklin, 10:38)
• “The product is you.” (Patrick Johnson, 32:34)

Tone:

The conversation is technical yet highly accessible, blending the rigor of data science with honest, sometimes skeptical reflections on the social, ethical, and practical implications of digital and virtual twin technologies.

Summary Takeaways

• Definitions are nuanced: "Digital twin" and "virtual twin" have distinct meanings—from realistic replicas to expansive, exploratory models.
• Applications are broad—but not without hype: Real industry adoption (aviation, urban systems) demonstrates value, but hype can blur lines between genuine innovation and branding.
• Challenges are perpetual: Representation (what’s included/excluded), interdisciplinary teamwork, adoption by practitioners, and alignment with human behavior remain unresolved.
• Ethics and privacy: As digital twins encompass more of human life, issues of consent, traceability, and data ownership come to the fore—requiring robust frameworks, especially where commercial interests prevail.
• Societal buy-in is crucial: Both guests emphasize the importance of public stewardship and innovating for societal benefit—going beyond technical achievement.