This is a revision of Freud’s “Project for a Scientific Psychology: General Scheme.” It updates the original, sentence for sentence where possible, in light of contemporary neuroscientific knowledge. The principle revisions are as follows. (1) Freud’s conception of “quantity” (the precursor of “drive energy”) is replaced by the concept of “free energy.” This is the energy within a system that is not currently performing useful work. (2) Shannon’s conception of “information” is introduced, where information is equivalent to unpredictability, and is formally equivalent to “entropy” in physics. (3) In biology, the fundamental purpose of “homeostasis” is to resist entropy – i.e., to increase predictability. Homeostasis turns out to be the underlying mechanism of what Freud called the “principle of neuronal inertia.” (4) Freud’s conception of “contact barriers” (the physical vehicles of memory) is linked with the modern concepts of consolidation/reconsolidation, whereby more deeply consolidated predictions are less plastic (more resistant to change) than freshly consolidated ones. (5) Freud’s notion of sensory “excitation” is replaced with the concept of “prediction error,” where only that portion of sensory input which is not explained by outgoing predictions is propagated inwards for cognitive processing. (6) Freud’s conception of “bound” (inhibited) cathexis, the main vehicle of his “secondary process” and voluntary action is equated with the buffering function of “working memory”; and “freely mobile” cathexis (the vehicle of Freud’s “primary process”) is equated with the automatized response modes of the nondeclarative memory systems. (7) Freud’s notion of ω (the system “consciousness”) is replaced by the concept of “precision” modulation, also known as “arousal” and “postsynaptic gain.”
