Can a physical universe exist without consciousness

The mysterious consciousness

How is consciousness related to the brain? And how can consciousness even exist in a physical world? Philosophy has tried to solve these puzzles for centuries.

Scientific supervision: Prof. Dr. Tobias Schlicht

Published: 08/28/2013

Level: medium

  • For centuries philosophy has tried to answer how consciousness fits into the physical world and how body and mind are related to one another.
  • Philosophy basically offers two different approaches to solving the body-mind problem: According to dualism, material and spiritual things are two completely different phenomena. Monism, on the other hand, assumes that there are only physical things and processes.
  • The interactionist dualism claims that body and mind interact with one another.
  • Epiphenomenalism believes that causal work is only one-way. Activities in the brain cause mental processes. Conversely, however, consciousness cannot influence physical processes.
  • Eliminative materialism goes a radical step further and denies that there is such a thing as consciousness.
  • Identity theory regards consciousness and physical activity in the brain as identical. Ultimately, consciousness would be nothing more than brain processes.
  • Opponents of this view point to the fact that it feels in a certain way, for example to be in pain. Brain processes could not explain this.

The Australian philosopher David Chalmers criticizes both identity theory and functionalism. All attempts to bring consciousness back to physical foundations have failed. For him the consequence is a return to dualism. However, he does not represent a dualism of substances, as Descartes proclaimed, but a dualism of properties, physical and phenomenal.

According to Chalmers, it would even be conceivable that consciousness - in the narrow sense of qualia - could be a fundamental building block of a physically understood world. If consciousness were an irreducible quantity, similar to mass or energy, then perhaps there is more or less consciousness in every living being or even in every inanimate object, depending on the complexity of the being or thing in question. It would then be "somehow" to be a blade of grass. But such panpsychism, according to which everything is animated with consciousness, is difficult for many philosophers to accept.

Some materialists view consciousness and other mental phenomena as pure functions that can be realized in different ways. Once you figured out how your heart worked, you could develop artificial hearts. Similarly, if consciousness were not a biological phenomenon, one could in principle also create artificial consciousness, according to the train of thought, by programming a computer in the right way, for example. Such functionalism represents a flexible alternative to the biological approach. However, one is far from knowing the function of consciousness, so that one could write a computer program on this basis that would then evoke a subjective perspective in an artificial being.

The philosopher David Chalmers (see also the box “Everything is animated”) differentiates between two types of problems of consciousness: The “difficult” problem consists in explaining how subjective experiences such as a directly experienced stabbing pain come into the physical world. A lot is known about how pain is processed in the brain. But even if one were to know all the relevant physiological mechanisms, one could not explain the subjective quality of the experience. In the case of the “simple” problem, on the other hand - mental phenomena without subjective experience content such as learning - it is sufficient to explain the underlying mechanism, because it is only a matter of a certain function being carried out.

The question of how consciousness and material interact with one another raises major problems. The solution to so-called psychophysical parallelism is idiosyncratic: it simply denies that the brain and consciousness interact with one another. Instead, they would just run right next to each other. For example, every act of will is accompanied by a certain activity in the brain. The philosopher and polymath Gottfried Wilhelm Leibniz (1646-1716) illustrates the relationship between body and mind with two synchronized clocks. God himself coordinated the two. From today's perspective, this is an unsatisfactory answer.

It's a somewhat unusual place for a tour: an enlarged brain that you can walk through like a factory. Interested visitors visit the upper room of a person under the guidance of a competent brain researcher. Using a realistic object, he explains clearly how nerve cells are structured and what messenger substances are there. But despite all the explanation, the visitor leaves one aspect unsatisfied, as the Swiss philosopher Peter Bieri observes in his thought experiment: “Nothing about what has been shown to us seems necessary for someone to experience something: not the type of Materials, not the structure of the factory, not the chemical reactions, not the electrical patterns. "

Consciousness in a physical world

Consciousness is a mystery, especially against the background of a scientific worldview. Because it remains unclear how something as subjective as consciousness can enter a physically describable universe. Mountains of material from neuroscience suggest that neural and mental processes are closely related. But it is difficult to imagine how the highly complex experience and a subjective inner perspective can come about from the gray masses.

Philosophy has been concerned with the question of how body and mind are related to one another since ancient times. In the 17th century, the French philosopher René Descartes (1596−1650) raised the so-called mind-body problem. Roughly speaking, philosophy offers two fundamentally different approaches: Dualism tries to prove that material and spiritual things are two different phenomena. For monism, on the other hand, there is ultimately only the world of the material. He often sees the mental as an illusion or something that is ultimately physical.

Descartes himself started from two essentially completely different substances. On the one hand there are the physically extended things, the res extensa. On the other hand, there is an intangible area, the res cogitans, which is characterized by thinking. Despite the essential differences, Descartes assumes that the two substances interact. Mental phenomena such as acts of will can influence activities in the brain. Conversely, physical things, such as irritation of the sensory organs, have an effect on consciousness. The so-called interactionist dualism has the advantage that it corresponds to our intuition: For us, conscious experience is something completely different from inanimate matter. Nevertheless, we believe, for example, that pain sensations influence our physical behavior, such as making us cry out.

But it is precisely this “outside” influence, of the immaterial spirit on the material world, that gets the interactionist dualists into trouble. Because it would change the total energy of the self-contained physical world. But this is not possible according to the physical law of conservation of energy.

Consciousness as an ineffective accompanying phenomenon?

In order to escape the dilemma, some philosophers claim that causal activity only works in one direction. According to what is known as epiphenomenalism, consciousness is merely an accompanying phenomenon, an epiphenomenon of brain processes. For example, the pain we feel would be caused by pain centers in the brain. Our face, contorted with suffering, would not be caused by the pain felt, but in turn by physical processes.

In a famous comparison, the English zoologist Thomas H. Huxley (1825−1895) compared consciousness with the whistle of a locomotive. The steam engine produces the whistling sound. However, this in turn does not affect the machine. This position seems to have a tailwind from modern brain research. For example, the American neurophysiologist Benjamin Libet (1916-2007) came to a result that surprised him too in experiments: a readiness potential that occurs in the brain in the run-up to voluntary movements could even be maintained for a few hundred milliseconds in front measure the consciously experienced intention of test persons to move a hand. The act of will seems to be dependent on neural activity and even causally irrelevant. But not only these results are controversial (free or not free?), But also epiphenomenalism itself.

If he were right, everything would happen without consciousness - intuitively quite implausible. In addition: What evolutionary advantage should consciousness have brought if, as an ineffective accompanying phenomenon, it did not increase the chance of survival at all?

Consciousness eliminated entirely

Eliminative materialism goes a radical step further. He not only denies consciousness any causal force. He completely eliminates the area of ​​the mental. As a monistic approach, he only believes in the existence of physical things and processes. For the Canadian philosopher Paul Churchland of the University of San Diego, states of consciousness are ultimately nothing but artifacts of a prescientific theory that leads us astray. In order to explain and predict the behavior of other people, we would have started one at some point in the course of evolution Developing everyday psychology: We would have started to attribute states of consciousness such as feelings, desires, beliefs and intentions to our fellow human beings. The fact that we have the impression that we are directly experiencing these mental states in ourselves is only due to the fact that we have become completely used to this everyday psychology and also explain our own behavior with it. Paul Churchland goes so far as to claim that one day we will completely do without the mental vocabulary! That is when neuroscientific theories explain the behavior of other people more precisely than everyday psychology.

A problem with this philosophical theory is not only that it is extremely contrary to our intuitions. Studies on patients with surgically severed cerebral organs also suggest that, for example, feelings can also be identified independently of language and thus before any theory. Our conscious experience would therefore not necessarily be shaped and bewitched by everyday psychology.

Consciousness identical to brain processes?

Identity theory is a little less radical. According to her, the mental, like feelings and sensations, does exist. But it is identical to physical events in the brain, even if it presents itself to us in two different ways, as a subjective experience and as an objectively measurable brain process. But even this attempt to explain has a catch, a particularly big one. Conscious experience and neural activity seem to have completely different properties. For example, we experience our consciousness as uniform. On the other hand, there is a hardly manageable number of parallel and distributed neuronal processes running across the brain. Conversely, from a qualitative point of view, consciousness is tremendously diverse and multifaceted. Just think of the infinite variety of smell experiences and touch sensations. On the other hand, the qualitatively monotonous pattern of neuronal activity seems very monotonous.

What distinguishes the numerous brain processes that remain unconscious from those that we also experience consciously? So far, no attempt to explain why a certain neuronal activity in the brain should be experienced in a certain subjective way has been made understandable.

What it's like to be a bat

For quite a few philosophers, a deep rift opens up at this point - between our internal perspective and the external perspective of the empirical scientist. One aspect of consciousness in particular causes headaches for die-hard materialists: the so-called qualia. It feels a certain way to taste a tomato or feel a pain. The American philosopher Thomas Nagel of New York University described the contrast between our objective and subjective knowledge in a famous essay. Even if we knew everything about the physiology of a bat, so Nagel's example, we would not know “what it is like to be a bat”. The American philosopher Joseph Levine from the University of Massachusetts in Amherst speaks of an explanatory gap that cannot be bridged in principle. Ultimately, none of the parallel activities in the brain make it clear why something is experienced by a subject as a result. In the attempt to equate consciousness and the physical, there remains an explanatory gap.

Despite many interesting solutions, the philosophers have so far not been able to crack the riddle of consciousness. Will neuroscientists fare better? One can be curious.

for further reading:

  • Pauen, Michael: Basic problems of the philosophy of mind. An introduction. Frankfurt 2001.