Post-modernism is generally seen as to some degree in conflict with popular realist accounts of science. However, I have come to the conclusion that successful theories in science support some of the key claims of post-modernism.

To explain why, we have to briefly turn to the "Scandal of Deduction."

The Scandal of Deduction

In any deductively valid argument, the conclusions must already be implicit in the premises. From this, it follows that no new information is generated by deterministic computation in the form of logical operations, nor by deduction in general. On the face of it, this widely accepted proposition, the “scandal of deduction,” seems ridiculous. Deductive arguments appear to carry information; they reduce our uncertainty. Data analysis software seems to tell us new things about our data, etc.

Prior attempts to analyze this disconnect have tended to focus on less popular semantic theories of information as a means resolving the problem. My contention would be that it can be explained entirely within the framework of Claude Shannon’s foundational theory of information.

Shannon’s theory shows how information flows from a source to a destination. Information is transmitted across achannel. The channel is the medium through which a signal passes from the information source to a receiver (e.g., between a physical system and a measuring device). Thereceiver then “reconstructs the message from the signal,” making it available to a destination, “the person (or thing) for whom the message is intended.”



The key to resolving the Scandal of Deduction is to realize that computation itself, and the activities of the human brain, all involve ongoing communication. We tend to think of the “destination” in Shannon’s theory as a unified entity, but this is only true in the abstract. We might think of the text of this post as the signal in Shannon’s model, the space between our eyes and the screen as the channel, and our eyes as the receiver, but this is too simple. Our experience of sight is the result of an extraordinary number of neurons computing and communicating together. We could as well talk of electrical activity down the optic nerve or the collective action of some neurons in the visual cortex as the signal vis-à-vis different stages of the process. Cognitive science tells us there is no one “destination,” no Cartesian homunculus, who ultimately understands the message; consciousness is an emergent process.

Likewise, in the archetypal example of a Turing Machine there is communication after an input has been fed to the machine. The head of the machine has to read the tape. Nothing in the Turing Machine is a “destination,” that receives the entire output at once, just as no single neuron understands a message and no single logic gate does computation alone. In the same way, “memory” systems can be seen as a form of communication between past states of a system and its future self.

The information entropy of an original message is not changed by computation; information sets an upper bound on the maximum reduction in uncertainty a recipient can receive from that datum alone*. However, the “Scandal” only exists if we assume all the information required to generate "meaning" exists in the physical signal of some message. This is obviously false, rocks do not gain information about logical truths if we carve them into them, meaning is not contained in signals alone.

A machine running an algorithm doesn't "know" the output of that algorithm before it is done computing for precisely the same reason that a communication cannot arrive at a destination before it has been sent. The enumeration of logical entailments in computation are causal processes and take time to complete-- the "Scandal of Deduction," comes from assuming that effects can precede their causes.

When we understand messages we “bring information to the table.” The initial signals we receive are combined with a fantastic amount of information stored in the brain before we become consciously aware of a meaning.

Messages do not exist as isolated entities in the real world; when we receive a message it is necessarily corelated with other things in the world. Indeed, Shannon Entropy can only be calculated in terms of the number of possible outcomes for some random variable in a message, but knowledge of which outcomes are possible, and their probabilities, requires background information.

The Relevance of Information Theoretic/Computational Accounts of Consciousness to Post-Modernism and Theories of Meaning

The information that signals are combined with in the brain varies by person and it varies according to the amount of cognitive resources that we are able to dedicate to understanding the message. "Understanding," is itself an active process that requires myriad additional communications between parts of the mind and the introduction of vast quantities of information not in the original signal.

This is why listening to someone read a passage while you are distracted versus meditating on/completing a "deep read" of that same passage can result in taking an entirely different meaning from the exact same signal. The semantic content of messages is thus determined not only at the individual level, but at the level of the individual instance of communication.

That said, the amount of resources we commit to understanding a message is dictated by not only conscious processes (i.e., executive function), but by unconscious processes. If we are angry, hungry, high on drugs, etc., the ways in which we understand are affected in ways that we often are unaware of. One other way our interpretation of signals is affected unconsciously is through social conditioning, norms, etc. So here, post-modernism has a point about how culture interacts with experience and meaning. This is not true simply of language, but of all of phenomenal existence, as all incoming sensory data is itself a "message."

For an example of this, consider how you are able to properly respond to someone without giving offense even when you are distracted and not really listening to what they are saying. Here, learned social norms of discourse are unconsciously dictating both the amount of meaning you glean from incoming signals (i.e., just what is needed to complete your part of the language game), as well as the signals you will produce in response.

A few other points:

• In a way, post-modernism is correct to reject the "universal validity" of binary oppositions. While it is true that some things imply their opposite, it is not true that all entailments are necessarily immediately accessible to us. This follows if we adopt some form of computational theory of mind, even a limited one. Per the analysis of the Scandal of Deduction above, we do not understand all the entailments of some proposition until we have actually finished the computation that enumerates that entailment. Further, depending on our conscious and unconscious priorities, we might not even preform such computations, so such "implied opposites" simply do not exist (for us) in some contexts. We must differentiate between entailment as an abstract, eternal relation, and entailment as enumerated in physical computation.
  
• Derrida's claim, following Sausser, that signs gain their meaning through contrast with other signs alone is, in fact, completely in line with modern information theory. Taken with the point above though, we must keep in mind that even if a sign is defined in terms of oppositions, we need not always have all those oppositions present within conscious awareness to understand part of a sign's meaning. This seems to flow with the ideas behind deconstruction.
  
• The "belief that phenomena of human life are not intelligible except through their interrelations," and that "these relations constitute a structure, and behind local variations in the surface phenomena there are constant laws of abstract structure," Blackburn's description of structuralism, could as well be applied to an information theoretic understanding of cognition. Cognition, in this account, involves introducing a vast amount of information into our active understanding of signals, and this is only possible because we are equipped to map commonalities onto one another.
  
• Information theory gives us the tools to explain how it is that incorporeal entities such as recessions, cultures, laws, etc. can exist within a physicalist ontology and causally interact with the world. Such theories of incorporeal entities necessarily share a lot of similarities with structuralism. Moreover, they offer us a way to understand how entities like culture or zeitgeist can both exist in the world and have a causal role in our perceptions.
  
• An information theoretic model of consciousness suggests that something like Bachelard's proposed "epistemological obstacles/breaks"—"or unthought/unconscious structures that were immanent within the realm of the sciences," are not only possible, but likely to exist.
  
• Post-modernism may overstate the justification for the linguistic turn. When we understand words, we use our entire sensory system. The same system used to process vision is used to imagine or remember images. Likewise, the auditory cortex processes incoming sounds, and also works to help us imagine sounds. Thus, the line between "language" and "phenomena," is artificial. Language is not some distinct thing we do that cuts us off from "non-linguistic phenomenal existence," rather language does its job by utilizing the same systems that give rise to phenomenal existence itself.
  

* To see why, consider that a program which randomly generates a page of text will eventually produce every page that will ever be written in English: the pages of a paper on the cure for cancer, the pages a proof that P ≠ NP, a page accurately listing future winning lottery numbers, etc.

However, the information contained in messages is about (corelated with) their source. Even if such a program miraculously spawned several pages that purported to hold the cure for cancer, there would be almost no chance that it corresponded to a real cure for cancer, since there are far more ways to write papers on incorrect cures for cancer than there are ways to write a paper about how to actually cure cancer. Any messages from such a program only tell us about the randomization process at work.