What is consciousness?

In his biography of Leonardo DaVinci, Walter Isaacson points to a theme that Leonardo returned to often—understanding how human beings fit into the grand order of the universe. This theme was made most explicit in Leonardo's drawing of the Vitruvian man. Leonardo studied art and science with the most intense curiosity to understand the connection between our own nature and the universe.


Our knowledge of art and science has grown immensely since Leonardo. And yet the same question is still with us. How do we fit in with our conception of the universe? We think of ourselves as conscious beings possessing rationality, creativity, meaning, and free will, while we think of the universe as purely mechanistic, consisting wholly of mindless, meaningless, physical particles in fields of force. 1 The question of how we fit in is one of the central questions of contemporary science and philosophy. The key to making sense of how we fit in with the universe lies in understanding the nature of consciousness. In this post, I will say a few things about the nature of the definition of consciousness and what consciousness is.

There are many theories that attempt to explain what consciousness is, how it works, and how the mental relates to the physical. These theories go by the following names: substance dualism, property dualism, materialism, physicalism, computationalism, functionalism, behaviorism, epiphenomenalism, cognitivism, eliminativism, panpsychism, biological naturalism and more. There is currently no consensus among experts about which theory is most correct, and there are many unanswered questions about consciousness. Some even argue that we can never fully understand it. 

Currently, the study of consciousness is more of a philosophical issue than a scientific issue. Philosophy differs from science in that science tries to answer questions for which there is a systematic or agreed-upon way of answering those questions. Philosophy, on the other hand, deals with questions for which there is no systematic way of answering those questions. This doesn't mean that consciousness can never be a scientific issue. All issues that are now scientific were once philosophical issues. This explains why early scientists such as Isaac Newton were called "Natural Philosophers". Once a philosophical issue develops enough, it often becomes a scientific issue (though some issues are so fundamental that they will never become purely scientific in the sense described above).

We currently do not have a scientific definition of what consciousness is. We only have a common-sense definition. To illustrate the difference between scientific definitions and common-sense definitions, think of water. A scientific definition of water is that it is H2O. A common-sense definition of water is that it is a colorless, tasteless, liquid. We can still understand a lot about water with just a common-sense definition.

In my experience, people often resist defining consciousness. In some cases, it seems that they assume that if there is no scientific definition then you cannot meaningfully talk about consciousness at all. I think this is mistaken. We can make a lot of progress even if the concepts we are using are not fully understood. This is more common in science than many people think. I believe that we can give a definition of consciousness that is a useful starting place even if it is not perfect or fully complete.

A common-sense definition of consciousness goes something like this:

Consciousness is our everyday experience of awareness. It is our experience of reality as well as our own 'inner' states such as dreams or pains.

Examples of consciousness are often described by what we experience through our senses— hearing a bird singing, looking at the sky, feeling rain on your face, touching a rose, etc. Consciousness can also take the form of feelings and emotions or other bodily sensations such as a tickle or a toothache. A specific conscious experience can be pleasant or unpleasant. 

Consciousness is also subjective, meaning that it is experienced by a subject or agent. In technical terms, consciousness has a 'first-person ontology'. Just because it is subjective does not mean it cannot be studied by science. There can be an objective science (in an epistemological sense) about a domain that is subjective (in an ontological sense). The feature of subjectivity is perhaps the cause of the most difficulty concerning consciousness.

Everything that we value in life—science, art, society, etc.—depends on the existence of consciousness. Consciousness is the most important thing in our lives because it is a necessary condition for anything to be important to us at all.

Some relevant questions about consciousness that interest me include:

  • What are the features of consciousness? (in addition to a few mentioned above)
  • Which theory of consciousness is most accurate / best explains our scientific understanding?
  • What is the connection between consciousness and the brain? How does the brain cause conscious experience?
  • Is the brain a digital computer? Is the mind a software program? Can a computer be conscious?
  • How do we understand the concept of the 'self'? 
  • How do we explain our experience of free will? Do we even have free will?

I hope to write more about specific questions and issues related to consciousness and how it fits into our contemporary conception of reality.


1. See Freedom and Neurobiology 2007