Science Seminars

What Is Information?

Speaker: Juan G. Roederer (LASP)
Date: Thursday, Jan 16, 2020
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

No, I will not talk about Shannon’s mathematical theory of communication (he and Weaver explicitly declined defining “what information is”), nor about the physicists’ usual view of “information as the resolution of uncertainty” (BTW: What is “uncertainty”?), nor on space data handling.  Rather, I will try to define the concept of information in an objective way, independent of human experience. To accomplish this I will start with the concept of interaction between material bodies and identify two distinct categories: 1) Interactions which can always be reduced to a superposition of physical interactions (forces) between elementary constituents; 2) Interactions between complex macroscopic bodies in which this is not possible but where patterns (in space and/or time) play the determining role. Pragmatic information is then defined as the correspondence between a given pattern in one of the bodies (the source) and the ensuing pattern-specific change in the other (the recipient). I will show that pragmatic information is a purely biological concept that plays no active role in the purely physical domain (it only does so in the macroscopic domain when a living organism—in science, the observer—intervenes). The consequences for physics and biology will be briefly discussed, including three fundamental transitions: from the quantum to the classical domain; from natural inanimate to living systems; and from subhuman to human brain function. Why is this relevant to space research? Because an important task today is the detection of life in other parts of the universe—and only life systems are capable of information-driven interactions (for a review, see J. G. Roederer, Phil. Trans. R. Soc. A 374: 2015.0152).