The currents of time carry us onwards, until the day comes when we can swim no longer. We are not wholly gone, for the ripples of our actions continue to touch the lives of others, a pattern whose breadth and beauty defines us.

Few patterns are as beautiful as that of Ben Barres.

I met Ben in person only once, in 2014. After that singular meeting we continued to correspond, often enough that I considered him a mentor. Even so, I cannot say I knew him well.

One need not know a person well to see their inner light.

Much has been written of Ben's passion, courage, and brilliance. There are several lovely epitaphs to his life and work – ethical, social, and scientific – woven from tales shared by those whose lives he touched.

One of his last efforts was a public call to ensure that postdocs can take their projects with them when they start their own labs, free of competition from their former advisor. In Ben's memory, this is a pledge I make gladly.

We will not see his like again.