something; the maximum number of bits that may be processed in one location; the total number of bits available in the Universe; etc. However, whenever physicists use the term information in statements in a qualitative, descriptive way such as “the field carries information about its sources”; “information cannot travel faster than light”; “information about the microstate of a gas”; “the detector provides information about the radiation background”; “information deposited in (or extracted from) the environment”; etc., they are really talking about *pragmatic information*.

In effect, it is mostly the biologists, particularly geneticists and neuroscientists, who make an explicit distinction between Shannon or statistical information (detached from purpose or effect), algorithmic information (minimum number of binary steps to define something, or the numerical values of physical variables) and pragmatic information (linking purpose and effect) (e.g., see Küppers 1990). Of these three classes of information the last one is usually the most relevant in biology; indeed, the notion of *quantity* of information is often of secondary importance: what counts is what information ultimately *does*, not how many bits are involved.

As we argue in Roederer (2005), pragmatic information is a purely biological concept. This seems quite difficult to accept for physicists, not 