David Spergel: Cosmologist, Mentor, and Friend

5 min readApr 12, 2021

Get free notes and resources delivered weekly to your inbox; Please join my mailing list; click here 👉 http://briankeating.com/mailing_list.php 📝

David Spergel, incoming president of the Simons Foundation

Key Takeaways

“We’re in this interrupt world of email and Slack, and if you want to think deeply about things you need to set aside blocks of time to think.” Dr. Spergel
While awards are not everything and shouldn’t be the main motivation for academic research, winning them gives you the opportunity to take risks later on.
Dr. Spergel thinks that leadership is a skill that can be learned like anything else.
He views leadership like playing a sport: you can get better with practice, by reading about it, and with coaching.
It’s a mentor’s job to instill the self-confidence needed for their mentees to succeed.
Even if you spend years going in the wrong direction, it can often lead to unexpected success later on.
For debate to be fruitful, all participants need to agree to two principles:

While string theory and ideas of the multiverse are interesting and fun, they ultimately aren’t falsifiable. Funding is limited and difficult to acquire, so research should be focused on what can be disproven experimentally
“I believe in the scientific enterprise. I think one of humanity’s great accomplishments, and certainly one of the great accomplishments of the last few hundred years, has been our deepening understanding of the universe.” Dr. Spergel

David Spergel (@DavidSpergel) is an American theoretical astrophysicist. He is the Director of the Center for Computational Astrophysics at the Flatiron Institute and the Charles A. Young Professor of Astronomy on the Class of 1897 Foundation, Emeritus, at Princeton University.
Host: Dr. Brian Keating (@DrBrianKeating)
In this conversation, Dr. Spergel talks about motivation and aiming for academic prizes, what it takes to be a good leader and mentor, how failure can lead to success, the efficacy of debate, controversies in physics, and what it all means.

Dr. Spergel maintains a fairly busy schedule.
Most of his day is spent reading papers and meeting with graduate students and post-docs about their work.Once the rest of his day starts to fill up, he tries to avoid dealing with emails.
He prefers to use his free time for thinking.
“We’re in this interrupt world of email and Slack, and if you want to think deeply about things you need to set aside blocks of time to think.” Dr. Spergel

Dr. Spergel’s primary motivation in his career hasn’t been awards, but rather the joy of learning.
He enjoys mentorship and watching people grow and develop.
He also finds himself on a lot of prize committees these days.
He seeks to reward people who can be held up as a model for younger physicists
But awards do come with other benefits
“If you have made a significant contribution and it gets recognized, it gives you opportunities to do new things in the future. To me, that’s the biggest benefit to winning the Nobel prize.” Dr. Spergel
He considers the MacArthur Fellow to be the most valuable prize he’s won because it provided him with the resources needed to focus on work instead of money at an early stage in his career.

Dr. Spergel thinks that leadership is a skill that can be learned like anything else.
He views leadership like playing a sport: you can get better with practice, by reading about it, and with coaching.
According to Dr. Spergel, the two most important things every leader should learn are to communicate clearly and have a clear message.
You should also have a clear vision of the intellectual culture you want to establish.
People should feel comfortable speaking their minds.
People should treat each other with respect.
“I think one of the most important phrases for all of us to learn is ‘I don’t understand.’ We should never be embarrassed to say I don’t understand.” Dr. Spergel
Another key piece of leadership is encouraging people to ask questions by creating environments where they feel comfortable doing so.
As a mentor to many students, Dr. Spergel thinks that the main thing students need is love. This he learned from Dennis Sciama, Stephen Hawking’s mentor as well as Lord Martin Rees.
It’s a mentor’s job to teach students basic skills but, more importantly, it’s their job to instill in them the self-confidence needed to succeed.
If you give students a sense of love, a sense of self-confidence, they’ll find an interesting project to work on and they’ll have the confidence to do interesting work in their field.

Some of Dr. Spergel’s most important work came from failure.
He spent four years working on an idea with a working model that generated a lot of papers. But then new data came to light that completely ruled it out.
Even though he wasn’t happy that four years of work had been undone, it did make him appreciate how quickly physics was moving forward.
So he decided to start thinking about the problem he’d been working on differently.
This led to a series of papers that pushed the field forward.
The failures of those four years going in the wrong direction, in a sense, led to the successes that followed in the subsequent years.

Dr. Spergel thinks the value of debate depends on the people involved.
One reason to engage the debate is if there are students listening who might not otherwise understand the weaknesses in someone’s argument.
But for many controversial views, Dr. Spergel thinks we’re seeing discussions that are about selling books, not about trying to understand the way the universe works.
For debate to fruitful, all participants need to agree to two principles:
falsifiable tenants that can be tested with data
fundamentally concerned with discovering the truth
There is, ultimately, a standard of proof for important claims.

As the president of a foundation that supports basic research, Dr. Spergel is mostly concerned with investing his resources into experiments that are likely to advance the field over the next 20–30 years.
He does admit that there have been impressive advancements made from the string theory techniques, even if they don’t rely on string theory itself.
But most of the work that he’s seen on the multiverse hypothesis isn’t very interesting.

“I believe in the scientific enterprise. I think one of humanity’s great accomplishments, and certainly one of the great accomplishments of the last few hundred years, has been our deepening understanding of the universe.” Dr. Spergel
While it’s true that the outcomes of science have increased knowledge and led to technologies that have made life worse, it’s also true that a smaller fraction of the human population goes to bed hungry.
The world is fundamentally in a better place due to the advances of science and he feels fortunate to be able to contribute to those advances.
He thinks his greatest contribution will be through training students the right way.