If you show an autistic child a
closed box of candies, and ask him what's inside, he'll answer that it's candies.
Suppose you then open up the box and show him that instead of candies, someone
has put a crayon inside. Then you tell him that you are going to show the
closed box to one of his friends (who has not seen that the candies have been
replaced with a crayon), and you ask him what he thinks his friend will say is
inside, he will answer “a crayon”. Normal children and children with
Down’s syndrome will pass this test with no problem, but not autistic children,
who do not seem able to imagine other people’s mental states.
Not all theories that attempt to
explain the emergence of human consciousness are based on the complex social nature
of human groups. Michel Cabanac, for example, thinks that consciousness
may have evolved from sensation. The conscious aspect of our
sensations would therefore be the first element of consciousness to have emerged
in phylogenesis, even before the advent of reptiles.
Cabanac also shows
that every conscious mental object has preserved the structure of its sensory
origins. In other words, it is characterized by four dimensions: its quality (its
nature ), its intensity (if a lion walks into the room, it attracts our attention
more than if one of our co-workers did), its hedonicity (whether it is pleasant,
unpleasant, or neutral), and its duration in time.
This postulate, Cabanac
argues, would explain why pleasure has become the “common currency in the
tradeoffs between motivations”, with our behaviours being optimized by the
THE FUNCTION AND EVOLUTIONARY ORIGINS OF CONSCIOUSNESS
For many people, this implies that consciousness
must have given some advantage to those species that evolved a particular form
of it. That is why so much has been written about the possible functions of consciousness:
the question of its origins is intimately linked to the role that we ascribe to
One of the most common approaches
is to say that consciousness may have helped in solving
the kinds of problems that our primate ancestors encountered. Because most
primates live in social groups, each individual must deal with serious problems
arising out of his or her complex relationships with the other members of the
group. For this reason, many authors think that the evolution of our intellect
occurred much more in response to the complexities of this social world than in
response to the physical environment.
we can properly consider these social theories of the origin of humanconsciousness, we must remember that merely forming a society
in no way guarantees that a species will evolve a large brain that is capable
of being conscious. For example, ants form societies but do not recognize themselves
as individuals. Every ant is interchangeable with every other, because they all
display the same behaviour, which is genetically determined in their nervous system.
In contrast, those animals that learn
most of their behaviours are not so readily interchangeable. Every individual
has its own habits and its own temperament. Hence it becomes important for the
members of a group to be able to distinguish one another visually, so that they
can know, for example, who is willing to share food with them, who is likely to
help them fight off predators, or who may potentially return a favour. It was
in this way that the specialized neuronal system that performs facial
recognition may have evolved, because it confers a definite evolutionary advantage.
to operationalize this advantage, individuals must be able not only to recognize
each of the other members of their group individually, but also to predict
how each of them will behave. It is this ability to develop a “theory
of mind” regarding other individuals that people suffering from
autism seem to have lost (see sidebar). But if our brains function normally, then
when we meet other human beings, we immediately tend to attribute certain mental
states to them. This predisposition is so strong in human beings that it can be
triggered by any object that can be identified as an agent capable of intentionality.
Indeed, since the dawn of time, human beings have
attributed human-like intentions to wild and domestic animals, the planets, the
wind, the sea, volcanoes, and, more recently, even to cars and boats.
In fact, we will
even ascribe mental states to any geometric shape that moves or changes spontaneously.
For example, anyone who watches the animation to the left will surely understand
that the big black triangle “frightens” the little red circle and
the little blue square, then chases them around until it herds them into the black
enclosure and traps them inside. And yet all we are really seeing are geometric
shapes moving around on a flat surface.
the course of their development, children gradually come to understand that
other people have desires, intentions, and motivations—in short, a different
perspective from their own. Many authors believe that consciousness
of self emerged gradually over the course of evolution as social groups became
more complex, thus conferring an advantage on individuals who could put themselves
in someone else’s skin.
Humphrey, for example, believes that it was this development of a theory of
mind for other people that eventually gave us the ability to construct a theory
of mind applied to ourselves and thereby recognize our own desires, intentions,
and motivations—in other words, the beginnings of something like subjective
Derek Denton offers
another theory of the origins of human consciousness, one according to which these
origins were not social. For Denton, even before there is sensation of the exterior
world, there is perception of the interior one. Thus he believes that consciousness
appeared with the “primordial emotions” such as pain,
hunger, thirst, and sexual desire, or the need for air or the sensation of suffocating.
These emotions tell the organism that its existence is at stake; they impose themselves
on the organism and push
it to act.
According to Denton, the first signs of consciousness
therefore manifested themselves very early in
the course of evolution. The first mammals (and even evolutionarily
older animals, such as the cuttlefish) that succeeded in creating “mental
scenes” to adapt their behaviour to the vital needs signalled by hunger
or thirst may have thus improved their chances of survival.
Some authors have suggested
that one way to overcome the determinism of nature would be to add an element
of chance, somewhat like the probabilistic
approach in quantum physics. But this proposal leaves many of them
dissatisfied, because ultimately, it does not mean what they would like it to
mean: that their own efforts, and not just luck, make a difference in the way
they lead their lives.
Questioning whether our consciousness
is the first cause of our voluntary actions does not necessarily cast doubt on
the role that rational deliberation definitely plays in our decisionmaking. Weighing
the pros and cons of a course of action, whether you do so with your conscious
reasoning or your unconscious emotions, is something very useful and, indeed,
something that has been selected
for very broadly by evolution in the animal kingdom.
THE QUESTION OF FREE WILL
If they had to give
out an award for the most hotly debated philosophical question in history, the
prize would probably go to the question of free will. At first glance, nothing
might seem more natural than to think that all of us are the authors of our own
actions. But even in the very earliest days of ancient Greece, a growing awareness
of the determinism of the laws of nature began to shed doubt on just how much
free will human beings had.
Because if the
universe follows deterministic laws, then everything that happens is inevitable,
and there is no longer any place for our free will. As you can imagine, this argument
that everything we do is determined by causes beyond our control has important
moral implications —in other words, social implications for our relationship
with other people.
On one side of the
resulting vigorous debate are those who see a major incompatibility between this
position and free will: they say that if the universe is deterministic, and given
that we are part of it and necessarily subject to its laws, then free will
can be nothing but an illusion. On the other side of the debate are those who
advance various arguments to attempt to salvage free will and make it compatible
with the deterministic nature of the universe (see sidebar).
have a strong incentive to do so, because our sense of being the source of our
own actions is very powerful. At any given moment, we naturally feel that it is
“we” who are causing our actions by consciously deciding to take them.
The question of free will can therefore be restated as follows: does voluntary
consciousness in fact play a role in our decisionmaking?
analyze this question more clearly, we must first draw a distinction. It is one
thing to say that there can be an agent who can cause a certain number of effects
in the world; it is another to say that voluntary consciousness is the first cause
of these effects.
Human beings, like
any other animals, are very definitely agents, in the sense that they are constantly
acting upon the world around them. But do the voluntary
movements that are the source of their actions originate in their consciousness?
That is the question.
One tool that may help
us to answer this question consists of brain-imaging technologies that let us
observe the dynamics of the neuronal activation associated with voluntary actions
(follow the Tool Module link to the left). Using these technologies, scientists
have observed that our
gestures are initiated in the prefrontal areas of the brain. These areas then
send signals to the premotor
areas, which program the movements in detail, and then to the motor areas
that cause them to be executed. The process for language is similar: Broca’s
area produces the motor output signal that ultimately activates the muscles
of the mouth and larynx whereby we speak.
this is the case, we can refine our question a bit further and restate it again,
as follows: are we capable of consciously triggering the brain activity
that then seems to lead irretrievably to a voluntary action? For us to
have this capability, our conscious decisions would of course have to precede,
even if by only the briefest interval, the brain activity associated with preparing
and then executing our voluntary gestures.
the brain-imaging studies just described date from the 1990s, scientists have
known since the 1960s that when subjects are monitored on an electroencephalogram
(EEG), the EEG trace always shows a “readiness potential” preceding
any voluntary motor action: a large deflection in the trace, slightly less than
1 second before the action itself.
led neurophysiologist Benjamin Libet to conduct one of the most
controversial experiments in the history of the neurosciences. Libet simply
asked himself whether this meant that the individual experienced the conscious
desire to act slightly less than 1 second before any voluntary action. He reasoned
that if it is in fact the conscious decision that initiates the action, then this
subjective feeling of consciously wanting to take this action must occur before,
or at worst, at the same time as, the start of the “readiness potential”.
Libet therefore designed an experiment
in which he could time three moments precisely: the moment when the subject began
a simple voluntary movement such as flexing his or her wrist, the start of the
“readiness potential” on the EEG, and the moment when the subject
had the subjective impression of consciously deciding to make the movement.
showed that it was the readiness potential that began first, about 550 milliseconds
(ms) before the action. It was only after that—a good 350 ms later—that
the subject reported consciously commanding the movement, which finally occurred
200 ms later (see the figure below).
How can we interpret these results? They seem to show that conscious will
arrives far too late to be the source of the action. And if the brain can initiate
voluntary movements before a conscious will to make these movements even appears,
then what role is left for consciousness? Does this mean the end of free will?
In any case, this brings us back to the hypothesis
that our subjective consciousness may be only an illusion, as some have long argued
and as this experiment seems to demonstrate. But it is worth remembering that
an illusion is not something that doesn’t exist, but rather something
that is not what it appears to be.
subjective impression that we are at the origin of our actions might be quite
real but not what it appears to be, that is, not the first cause of all our voluntary
behaviours. If it is not, then we have to ask ourselves how we can learn to live
conceptions of free will.