Emergence is one of the big ideas in science: new levels of organization arise from simpler parts. Tornadoes, snowflakes, oscillating chemical reactions and sand dunes are examples of weak emergence. They are complex, but they follow from ordinary physics. Strong emergence was meant for something different in kind, above all life and mind. Historically it has been linked to vital forces or something spiritual, and even today some look to unknown physics, such as quantum effects, to explain consciousness. But there is no evidence of anything supernatural, or of new physics, behind life or mind, so the explanation should be found within ordinary physics.

A concept called the epistemic cut marks the boundary between continuous, rate-dependent processes and discrete, rate-independent ones. Analog and digital computation are a good example. Analog computers were widely used in the first half of the 20th century, but digital computers took over from the mid-century on. A common explanation is signal deterioration. But there is another explanation: A bit can stand for any symbol, independent of the hardware. Between analog world and digital processing there is a distinct cut, the epistemic cut, that allows abstraction and general information processing not possible with analog computation. The same kind of cut is found in life processes where discrete DNA code controls living organisms.

The concept of the epistemic cut was developed by the biologist and systems scientist Howard H. Pattee. His main aim was to understand the fundamental nature of life and its origin, but he extended the idea to computation and mind as well. I have long considered it a promising basis for understanding strong emergence. Today, October 5, 2026, would have been Professor Pattee's 100th birthday, but sadly he passed away just about two months ago. In his memory, I thought I'll publish this extension of his idea.