This section presents the empirical idea of consciousness. What consciousness is like before theories are applied to explain it. It is based on descriptions from the Historical Review.

The definition and description of consciousnessEdit

Before embarking on the analysis of consciousness it is important to have a definition of what it is that we are attempting to explain. The article below considers how empiricists have described consciousness. It shows that consciousness is the space, time and content of our minds (where the content contains intuitions and feelings).

Consciousness has both form and content. Our task as modern scientists is to discover how and where the form and content of empirical consciousness exists in the world.


Empirical descriptions of consciousness have been available in Western literature for centuries and in Eastern literature for millennia. It is often maintained that no-one can define consciousness but there is a large body of literature that gives a clear empirical description of it. Perhaps the claim that no-one can define consciousness is frustration at the fact that no-one can explain consciousness.

Weiskrantz (1988) asserted that "Each of us will have his or her own idea of what, if anything, is meant by consciousness..." and that insisting upon a precise definition would be a mistake. Koch and Crick (1999) stated that "Consciousness is a vague term with many usages and will, in the fullness of time, be replaced by a vocabulary that more accurately reflects the contribution of different brain processes."

But is consciousness really a "vague term" and should we each have our own idea of what it means? The empirical descriptions of Descartes, Kant and others are summarised below under the headings of space, time, qualia and awareness. These descriptions show that consciousness is not a vague term at all.

Space and TimeEdit

Kant (1781) argued that our minds must be capable of representing objects in space and time. Without space, objects could not be differentiated and would have no properties. Without representation in time, the concepts of succession of events and simultaneity would be unknown to us. Descartes (1641, Meditation V, 3) was also clear that imaginings and perceptions are experiences where things are arranged in space and time: "In the first place, I distinctly imagine that quantity which the philosophers commonly call continuous, or the extension in length, breadth, and depth that is in this quantity, or rather in the object to which it is attributed. Further, I can enumerate in it many diverse parts, and attribute to each of these all sorts of sizes, figures, situations, and local motions; and, in time, I can assign to each of these motions all degrees of duration." Descartes was, as was so often the case, well ahead of his time by describing continuity and dimensionality, the factors that define his view of space as an actual vector space accessible to mathematical and physical analysis (See section on Descartes for a full discussion.)

Gregory (1966) also pointed out that we see things as if they are projected into space around us. The idea of projection was implicit in Kant’s and Descartes’ descriptions, which are from the viewpoint of an observer looking out at contents of experience, but Gregory is explicit (although he believes that explanations based on the projection are absurd).

Kant and Descartes describe consciousness as something extended in time but it is Clay and James who draw this fully to our attention. James (1890) quotes E.R. Clay who coined the term "specious present" to describe how we exist for more than a durationless instant and then goes on to say: "In short, the practically cognized present is no knife-edge, but a saddle-back, with a certain breadth of its own on which we sit perched, and from which we look in two directions into time. The unit of composition of our perception of time is a duration, with a bow and a stern, as it were--a rearward--and a forward-looking end. It is only [p. 610] as parts of this duration-block that the relation of succession of one end to the other is perceived. We do not first feel one end and then feel the other after it, and from the perception of the succession infer an interval of time between, but we seem to feel the interval of time as a whole, with its two ends embedded in it." Notice how James’ observer is at an instant but the mind is stretched over time.

James’ mental time is probably not the same as physical time. Hermann Weyl, the Nobel prize-winning physicist, wrote that reality is a "four-dimensional continuum which is neither "time" nor "space." Only the consciousness that passes on in one portion of this world experiences the detached piece which comes to meet it and passes behind it, as history, that is, as a process that is going forward in time and takes place in space" (Weyl 1918). In other words consciousness has a way of containing events in the same order as they occur in the world but uses a mental time that is different from physical time.


A quale is an attribute of something that exists in our minds. The colour purple is a good example (Tye, 1997). Qualia appear to be exceptional and inexplicable; Churchland (1988) writes "How on earth can a feeling of pain result from ions passing across a membrane?". Descartes (Meditations VI, 6, 1641) clearly describes qualia.


Descartes, Locke, Hume, Reid, Kant and most other empiricist authors in this field describe conscious phenomena as if there is an observer in their mind looking out at qualia or feeling qualia in the space and time around about. Descartes and Kant thought that the mind must also contain a conceptualisation or intuition of the meaning of its space, time and content so that the qualia become grouped into objects, the objects into events and the events into meaning and expectation.

As Kant put it, we have "intuitions" about the relations between things. In modern parlance our conscious experience appears to contain the output from an unconscious processor; although Kant's term, "intuition," is a more scientific approach because it is an observation without assumptions about causes. If the present is extended in time, or "specious" as Clay put it, then many moments are available through which it is possible to apprehend both a question and its answer: the processor can frame the question and provide the answer. The observation that our minds extend through time means that this processor does not need to be recursive to provide the outputs we experience as intuitions (one moment can contain an intuition about another whilst both are in the mind).

Descartes (Meditations VI, 10, 1641) considered the origin of intuitions: "Further, I cannot doubt but that there is in me a certain passive faculty of perception, that is, of receiving and taking knowledge of the ideas of sensible things; but this would be useless to me, if there did not also exist in me, or in some other thing, another active faculty capable of forming and producing those ideas. But this active faculty cannot be in me [in as far as I am but a thinking thing], seeing that it does not presuppose thought, and also that those ideas are frequently produced in my mind without my contributing to it in any way, and even frequently contrary to my will." Descartes suspected that the ideas were formed unconsciously, probably in the brain.

Types of ConsciousnessEdit

It is sometimes held that there are many types of consciousness, Anthony (2001) lists: phenomenal consciousness, access consciousness, state consciousness, creature consciousness, introspective consciousness and self-consciousness. Anthony takes the view that these are all 'modulations' of the term consciousness and do not mean that there are in fact different types of consciousness. In other words these 'types of consciousness' are modulations of the intuition of content arranged in space and time that is the singular consciousness described by Kant and Descartes. According to this explanation access consciousness is the time extended form of processes in phenomenal consciousness, self-consciousness is the time extended form of bodily processes and inner speech etc.. As an example, if we say a word then think it soundlessly it is evident that inner speech is whole, time extended words coming from the vague direction of the vocal chords (or both ears), when we move a limb much of the whole movement is present in our experience as a set of displacements at the position of the limb and extended through time.

Observations and DenialsEdit

There can be little doubt that most descriptions of conscious phenomenology have described the same things although some have used terms such as 'continuity' for time and 'representation' for space. Our conscious experiences are the experience of being an observer that has qualia distributed in space and time around a point. This experience is imbued with intuitions.

Contrary to the views of Weiskrantz and of Koch and Crick there seems to be no need to await a definition of consciousness. It has been described for centuries. So why did these authors feel a need to suspend any definition?

The answer is that over the years there has been no widely accepted theory of how this empirical consciousness could occur. This led certain philosophers such as Ryle (1949) to question whether the description of consciousness was credible.

In most cases this sceptical analysis begins with an explanatory discussion of consciousness such as: if information travels from the observation to the observer then the observer contains the information so there must be another observer within to observe this second set of information. In this case the conclusion is that this implies an impossible homunculus or Ryle’s "ghost in the machine" so observation and observer’s cannot occur in the mind. This argument is wrong. The scientific argument should be: the observed form of conscious experience cannot occur if it relies on information transfer, therefore the hypothesis that information transfer is consciousness is wrong and some other explanation is needed. (This means that although the content of consciousness is derived from the senses via signals in neurones, conscious experience is not these signals flowing into a nexus). In science the observation is paramount and cannot be discarded because it conflicts with theory.

The process of discounting an observation when an explanation fails also applies to other aspects of consciousness studies. As Gregory (1988) put it: " 'If you can’t explain it – deny it' is one strategy for dealing with embarrassing questions such as 'what is consciousness?' ". If we discount these denials then the empirical observations of Kant and Descartes and the other empiricists are the bedrock of consciousness studies and consciousness can indeed be described as an observation containing the space, time and content of our minds (where the content contains intuitions and feelings).

This simple definition of the experience we call consciousness is internally consistent and can be expressed in mathematical language. Consciousness is a multidimensional manifold with vectors pointing towards the centre (the apparent observation point). The content can be both the input and output of processors that are external to the manifold.

Adapted from the article The description and definition of consciousness by Alex Green in Science and Consciousness Review (with permission of the author).

The viewing point and the observerEdit

Science begins with empirical descriptions. To experience consciousness simply lean back with your eyes open and listen. Consciousness is the observational space and time that is occurring and the vectors within it that point at the apparent viewing point. It includes bodily sensations, inner speech and the smell on and around things etc. Consciousness is experience itself, it is not usually an experience of the content of experience, experience is already there, arranged in space and time (see note below).

The illustration below shows the difference between an actual 3D part of the world, 2D representations of that part of the world, conscious experience itself with contents that relate to that part of the world and naive realism:


The apparent viewing point has caused considerable difficulty for many empiricist philosophers (although the British Empiricists tended to avoid it). When they have stopped describing conscious experience and tried to explain the viewing point they have often resorted to the supernatural: Descartes, Malebranche and Reid all explained the viewing point in terms of a supernatural soul at a point that does the seeing or experiencing. But none of the empiricists describe anything flowing into the viewing point, indeed nothing does flow or could flow into and through a point. The empirical truth is that the viewing point is a geometrical phenomenon, not the recipient of some simultaneous flow of everything in experience. Just look, your viewing point is where everything in experience is directed but things are not pouring into it and it, itself, is a point, it cannot and does not contain anything. This seems to be Aristotle's insight when he wrote "In every case the mind which is actively thinking is the objects which it thinks."

The field of vectors that are the content of consciousness are also difficult to interpret; some philosophers believe that they are in the brain and form a representation of the world whilst others believe that they are directly attached to things in the world beyond the body.

The empirical description of consciousness allows us to make a sharp distinction between the scientific activities of measurement and observation. Measurement is the change in state of a measuring instrument in response to an event in the environment. Observation is the occurrence of events in the geometrical manifold that is our conscious experience.

* Note: the term "experience of" should be reserved for things that act as a source of the content of experience, such as the QM fields that constitute the things that are sensed. We have an "experience of" a flower when signals from the flower are composed into the form of a flower in our experience. Sometimes there is an "experience of" the content of consciousness, for instance when intuitions about the content occur. See later modules for a discussion.

A note on Naive Realism, Materialism and EliminativismEdit

Science begins with observations but there are theories that maintain that our observation is not a property of our brains or hold that our observation should be discarded.

Naive realism is the belief that the viewing point is a geometrical point where all the light from the things we see is focussed. According to naive realism "seeing" is accomplished by looking from the point back up the light rays to the things in the world. It is a widely held belief even though physics, anatomy and experiment tell us that none of this does or could occur (See the section on vision).

It should be noted that naive realists and Direct Realists may not believe that there is a problem of consciousness because they believe that the form and content of conscious experience is the world itself beyond the body (ie: they believe that the form and content of conscious experience is not a phenomenon based on sensation that happens in the brain). These theories of consciousness (naive and Direct Realism) are discussed in depth in the following modules.

There is a world view called "nineteenth century materialism" or simply materialism which considers that only the present, durationless instant exists and that all things can be explained by flows from place to place. This world view is taught as school physics and is almost universal amongst those who have not pursued further study in physics and philosophy. It is an outdated theory that is not the accepted wisdom in modern physics.

Unfortunately materialism is so widely accepted that it leads to highly problematical concepts appearing to be obvious. As an example the extended present of our conscious experience was called "specious" and thought to be obviously wrong by Clay because it is incompatible with materialism (see section on the problem of time). Similarly it is "obvious" that we can only have experiences of things rather than containing things because, according to materialism, the present instant has no duration and is immediately non-existent; the extension of things in time can only be conceptualised by endless flows or recursions. The culmination of materialism is Eliminativism and Functionalism in which it is realised that our experience is incompatible with nineteenth century theory and so it is often declared that phenomenal experience is just an illusion that does not exist.


  • Churchland, P.S. 1988. Reduction and the neurobiological basis of consciousness. Chapter 14 in Consciousness in Contemporary Science. (Editors: Marcel, A.J. and Bisiach, E.). Oxford Science Publications.
  • Gregory, R.L. 1966. Eye and Brain. London: Weidenfield and Nicolson.
  • Gregory, R.L. 1988. Consciousness in science and philosophy: conscience and con-science. Chapter 12 in Consciousness in Contemporary Science. (Editors: Marcel, A.J. and Bisiach, E.). Oxford Science Publications.
  • Ryle, G. 1949. The Concept of Mind. Hutchinson & Co. London.
  • Weiskrantz, L. 1988. Some contributions of neuropsychology of vision and memory to the problem of consciousness. Chapter 8 in Consciousness in Contemporary Science. (Editors: Marcel, A.J. and Bisiach, E.). Oxford Science Publications.
  • Weyl, H. 1918. Space Time Matter. Dover Edition 1952, p.217.

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