While conscious experience has been discussed throughout history, the late 19th century saw a rise in physicalistic reductionism, which, in its more extreme forms, declared “consciousness” and kindred terms to be unscientific. In the 1920s B.F. Skinner defined the goal of “radical behaviorism” as the complete elimination of mentalistic concepts from psychology — about two-thirds of English content words. Skinner’s influence dominated well into the 1970s, and during that time it was extremely difficult for scientists to openly study cs cognition, voluntary control, personal identity, and similar questions.
By the 1980s philosophers and scientists started to return to consciousness. Philosophers like Daniel Dennett and scientists like Francis Crick strongly supported a return to scientific research. Since the 1980s a large literature has grown, with thousands of findings about visual awareness, coma and wakefulness, direct brain recording of binocular rivalry, and much more. The PubMed database shows almost 20,000 articles for the keywords “conscious brain.”
Many scientific studies use experimental comparisons between similar cs and uncs events. This “contrastive analysis” approach has been very fruitful. Dozens of techniques now permit conscious—unconscious comparisons. Any method that permits such comparisons can enlarge our understanding. The resulting empirical harvest has been very large.
Ambiguities
“Consciousness” has several meanings.
It is used in biomedical science to refer to the state of waking consciousness, as assessed by responsiveness to questions, commands, and mild pain, by the classical scalp EEG of waking, and by the ability to describe oneself and current events. We will use terms like “conscious state” or “waking state” for this specific meaning. However, in scientific work “consciousness” is also used to refer to the “dimension of conscious vs. unconscious brain events” — that is, as an experimental variable that allows us to study brain differences attributable to consciousness.
This usage is profoundly different from the first, since it involves a measurable dimension of variation.
Yet “consciousness as an empirical variable” is still commonly confused with the waking state or with subjectivity. They are linked, but not the same.
Historically, many basic scientific concepts emerged from similar periods of ambiguity. In daily life, heat refers to boiling pots and summer days. But with the rise of thermodynamics at the end of the 19th century, the scientific term heat came to mean a dimension of temperature variation with a true zero point at 0 degrees Kelvin, reflecting a wide quantitative range of random molecular activity in physical systems.
Thus in thermodynamic theory, heat came to mean something very different from its everyday meaning.
Similarly, in scientific usage the topic of “consciousness” now often means an empirical dimension of variation in brain activity between matched conscious and unconscious events. When we talk about “the topic of consciousness” in science today, we do not mean subjectivity alone. Rather, we refer to the “conscious-unconscious dimension,” which includes subjective experiences, but always compared to close brain analogues that are not conscious.
A classical example is binocular rivalry, where mutually incompatible stimuli are presented to the two eyes, which cannot be fused into a single gestalt. Only one of the two rivaling stimuli can be conscious (reportable) at a time, though the other often evokes some degree of visual processing. The Nikos Logothetis laboratory at the Max Planck Institute in Tübingen, Germany, has used direct brain recording in macaques since the 1980s to trace both the conscious and unconscious processing stream. While many other methods are in use, the Max Planck group has performed the most coherent long-term research program of this kind.
Third and finally, the English language also uses “consciousness of something” to refer to the specific contents of mental life, or what we will call “conscious cognitions” or “conscious percepts.” Given these ambiguities, it is essential to avoid vague language. Here we will use unambiguous expressions whenever possible.
Part I of my latest book, On Consciousness: Science & Subjectivity is about both conscious cognitions and the state of (waking) consciousness. While state variables are often studied separately from conscious contents, a complete account must include both.
(See thalamocortical system; and Part IV in which major features of conscious states and contents are detailed.)
Read more & order your copy of ON CONSCIOUSNESS: Science & Subjectivity – Updated Works on Global Workspace Theory
Global Workspace Theory (GWT) began with this question: “How does a serial, integrated and very limited stream of consciousness emerge from a nervous system that is mostly unconscious, distributed, parallel and of enormous capacity?”
GWT is a widely used framework for the role of conscious and unconscious experiences in the functioning of the brain, as Baars first suggested in 1983.
A set of explicit assumptions that can be tested, as many of them have been. These updated works by Bernie Baars, the recipient of the 2019 Hermann von Helmholtz Life Contribution Award by International Neural Network Society form a coherent effort to organize a large and growing body of scientific evidence about conscious brains.
