from Nathaniel Daw

I never really considered Sam a peer – more of a hero, to be honest. I suppose, in general, that that kind of undisguised admiration could get in the way of a friendship, but Sam treated it, like more or less everything else, with grace and tact.

I first met Sam in '99; I was a new Ph.D. student in Pittsburgh but spending my summers at the recently launched Gatsby unit. Sam, as has been said here repeatedly, was a postdoc there, where he stood out both academically and socially among a group that was exceptional in both dimensions (really!). Some years later, as a Gatsby postdoc myself, I often had occasion to think back on his example, and to try (and largely fail) to emulate it.

In his scientific work, I think Sam viewed himself as sort of a craftsman: collecting powerful tools, dissecting them, refining them, and applying them in new ways. He would speak modestly about this – once explaining that he had never written a proof, except insofar as he inherited the theoretical guarantees that were inherent in the tools themselves – but at the same time he believed strongly in this approach and was so clearly excited and driven by the possibilities of his toolchest.

That Sam’s work and his thinking were so grounded in this concrete, almost clockwork perspective was one reason that he was able to be so incredibly effective at communicating about them. Many of his memorable turns of phrase (which many of us have swiped) are also so physical: the goal of LLE was to build a “box” with “knobs” that would dial along the key dimensions of the input space; HMM algorithms could be described as involving “bees” flying between states, linear models as operating on “pancakes” in higher dimensional spaces. Although he made this, like everything, look effortless, Sam worked incredibly hard at developing the tools for communication much as he did for the research itself. Over the years, I remember watching him experiment with different presentational innovations. In the days of overhead projectors, he would construct sandwiches of multiple transparencies and slide them over one another to make animations. Once, he started his talk with the key to an elaborate color-coding scheme for his slides; my favorite was brown for statements that weren’t quite technically true: you could ask about the caveat afterward, if you wanted. One year, he discovered that if he laminated his NIPS poster, he could write on it with a dry erase marker. He took a great deal of pleasure, not just in the didactic possibilities of this, but also at the look of horror on the audience’s faces the first time they saw him whip out the marker and start scribbling all over his figures.

Much more important to me – though much harder to describe, and more painful to recollect – are Sam’s personal qualities. As others have mentioned, Sam served a sort of guide and provocateur for a group exploration of London’s nightlife (also the somewhat less adventurous nightlife of Whistler, BC, as others have wholly neglected). My first encounter with Sam’s legendary generosity was the way he would subsidize the graduate students' food and drink in our London outings – although he explained that this was a remnant of his socialist Canadian upbringing, I only later realized he was trivializing a fundamental trait of his character.

It was a pleasure and an honor to watch Sam grow up, always many steps ahead of me. Some steps were small. When he took his first faculty job, he decided that he really should no longer engage in his annual “NIPS flirtation” with a PhD student. Typical of his sometimes untethered spirit of sharing, he told me this by way of trying to set me (not yet faculty) up with the student in question.

Our final interactions all centered around the much bigger steps of family and fatherhood. Like so many of my colleagues, I was excited about all of the professional possibilities from Sam’s arrival at NYU. But as it happened, his arrival – to an apartment in our building – coincided closely with the birth of our son, so I saw little of him (or anyone) at work. Instead, Sam and Meredith were instantly and immensely helpful and thoughtful, repeatedly showing up unexpectedly at our door with various bits of advice and baby equipment we didn't yet realize we needed. Sam always patiently explained what each object was for, our son is now surrounded all day by Sam’s things.

Sam aspired to fatherhood before I realized it was something to aspire to, and it’s the calling that all his talents really point to. If I had to have a last experience with Sam, I am glad, then, (though “glad” is not really the word for somewhat less devastated) that it was this one. And if I have one regret that tops all the others, it is that I will never get the chance to learn more from Sam about how to be a father, as he perfects it all a few steps ahead of me; and of course that Aya and Orli, and Meredith, will not be able to enjoy his continued success at what, I am sure, would have been the thing he was most brilliant at of all.