“The infinite! No other question has ever moved so profoundly the spirit of man,” said David Hilbert, one of the most influential mathematicians of the 19th century. A subject extensively studied by philosophers, mathematicians, and more recently, physicists and cosmologists, infinity still stands as an enigma of the intellectual world.

What’s it like to face a faceless world? Acclaimed neurologist Oliver Sacks once apologized for almost bumping into a large bearded man, only to realize he was speaking to a mirror.

Professor Witten is a leading light of superstring theory and the only physicist to have won the vaunted Fields Medal, mathematics’ highest honor. Known for advancing a number of novel approaches in mathematics and physics, Witten opened up new vistas in 1995 when he unified five seemingly competing superstring theories into M-theory, which seeks to unify Einstein’s general theory of relativity with quantum mechanics.

For this year’s inaugural address, “The Future of Big Science,” Nobel laureate and physicist Steven Weinberg considers the future of fundamental physics, especially as funding for basic research is reduced. Weinberg will explore physics’ small origins, starting with the discovery of the atomic nucleus 100 years ago by a single scientist.

Extra dimensions of space — the idea that we are immersed in hyperspace — may be key to explaining the fundamental nature of the universe. Relativity introduced time as the fourth dimension, and Einstein’s subsequent work envisioned more dimensions still — but ultimately hit a dead end.

“Because it’s there” was George Mallory’s famous explanation for why he risked (and lost) his life trying to become the first person to summit Everest. We don’t all want to …