How is the biological embedded into the physical, the psychological into the biological, the cultural into the psychological? What these different areas have in common is that the properties of objects belonging to them are not only dependent on unchanging laws, but also on the history of the object. The underlying level provides mechanisms of storing information and processing information depending on the stored information. The mechanisms for storing and processing information can be described by a notion of laws, but the information is acquired from the environment or from random processes and it is the result of the history of the system. This historical information cannot be derived from the laws describing the mechanisms of storage and processing of information.
Another example of such systems is computers and systems built from them. The technological description of such a system describes a system for information storage and processing but it does not describe the stored information and the processing programmed by that information. For example, this text is published on a blogging platform. The description of the computers of this system does not include a description of all the content, like this article or articles other people, like you, might have put here. The system can at any time be viewed as a physical system and there is nothing mysterious going on, but the content cannot be derived from the way the computers work. The computers are universal in the sense that they don’t constrain the content and for just that reason the content is, in a way, independent of them. The content arises from a process of “perception”, i.e. people blogging and publishing articles. And no description of this system can ever be complete because new content not covered by a particular description can be added at any time, provided the people running the system extend the storage capacity as needed. The increase in storage capacity is necessary because on bit of the information cannot be derived from another so a compression into a simple “law” or “theory” is not possible. Each extension of the information extends the “theory” describing the system.
In a similar fashion, a description of humans in terms of neurons will not describe any particular human being but just the “platform”. A bottom up approach of neuroscience will, therefore, not carry us very far towards describing phenomena of psychology or culture. Just like the blogging platform may be changed by changes to its software, adding features, new “themes” etc., without changing the hardware, humans and their psychology and culture can be changed without any change so the genetically determined structure of the human brain. I therefore don’t expect a reduction of psychology or cultural studies to neuroscience. Any theory describing humans and their culture will necessarily be incomplete because extensions are always possible, simply because neurons provide a universal, i.e. programmable platform capable of storing information and processing information depending on the stored information. And the mechanisms programming the system are in turn programmable by information, thus potentially changing the “laws”.
Similarly, the properties of organisms cannot be derived from the laws of chemistry. You can describe a particular organism in terms of physical laws, but the structure of the organism is not something that emerges from the laws of physics in the way the structure of a crystal emerges from laws of physics. Instead, many of its properties are a result of evolution, i.e. of history. DNA provides a mechanism of information storage and the mechanism of transcription of genes provides a mechanism by which this information can be translated into a phenotype. A population of organism can be viewed as an information-accumulating system that produces single organisms as “experiments”, of which some survive.
To give you a metaphor, when you describe DNA, neurons or computer hardware, you describe the toy blocks, not what can be built from them.
Conversely, the reason for the small role that the concept of information plays in sciences like physics may be that physical systems that can be described by laws can be described without referring to a concept of information. Information comes in with historical processes and these result in systems whose behavior can be described by those laws only if you put all the stored information into the description. At any time, the system is a physical system but describing it without the information it contains gives you a nearly empty description just because such systems are universal, i.e. plastic and programmable. The stored information, on the other hand, cannot be derived from those laws but is the result of historical processes in which information is absorbed from the environment or produced in random processes. So in biology, psychology or cognitive science, in cultural studies as well as the science of programmable technical systems like computers or the internet, “information” and “history” become key concepts, closely linked to each other.
So just keep adding information, keep extending the whole thing by adding new posts to your blogs!
(The picture is from http://commons.wikimedia.org/wiki/File:LEGO_Bits_Box_2.jpg)