It won鈥檛 come as any surprise that you have your senses to thank for managing this feat at all. But which ones? It certainly wasn鈥檛 sight, sound, taste, smell or touch.

While schools still teach us that there are five senses 鈥� an idea that came courtesy of Aristotle and permeates popular culture 鈥� the count is at odds with science. Try grabbing an ice cube with one hand and a red-hot poker with the other, and tell me that what you feel can be encompassed by the favourite five. Go on a white-knuckle ride at any theme park and convince me that everything you experienced was down to sight, sound and touch. You probably had your eyes closed anyway. There is clearly more to sensation than these five categories. So how many senses do we have?

In some ways the answer depends on how we divide our sensory systems up. For example, we could classify senses by the nature of the stimulus. In this sense (as it were) there are just three types, not five 鈥� chemical (sensed as tastes, smells or 鈥渋nternally鈥�, as with blood glucose), mechanical (touch and hearing) and light (vision). Some animals also have electroreception or a magnetic sense. All these groups of sensation require quite different sensory systems. Something dissolving on the tongue and producing an odour which permeates up into the nose and fits into a receptor is quite different from the mechanical movement of a hair cell in the inner ear, or a photon hitting the retina.

But we could as easily subdivide these further, and define a 鈥渟ense鈥� as a system consisting of a specialised cell type responding to a specific signal and reporting to a particular part of the brain. For instance, taste could be seen not as one sense but five 鈥� sweet, salt, sour, bitter and 鈥渦mami鈥�, a Japanese word for the taste of glutamate, which gives us our sense of meaty flavours. Vision could be viewed as one sense (light), two (light and colour) or four (light, red, green and blue). In some animals there are retinal cells which respond only to movement. Some people might consider that to be yet another sense. Neurologists classify pain as cutaneous, somatic or visceral depending on where it is felt 鈥� but does this mean they are different sensory systems or are they simply a matter of geography on and in the body?

Many people would agree that they can sense temperature, pressure, touch, joint position (proprioception), body movement (kinaesthesis), balance and feelings associated with a full bladder, an empty stomach or thirst. But there are other monitoring systems in the body that we can never be even dimly 鈥渁ware of鈥� 鈥� sensing the pH of the cerebrospinal fluid would be an example.

And take hearing. Is this one sense, or many hundreds, one per cochlear hair cell? That is probably taking things a bit too far, but it is interesting to note that we can lose high-frequency hearing without losing low-frequency acuity, and vice versa. So maybe they should be thought of separately. The more we study the structure of our sense organs, the more senses we appear to have.

But, intriguing as all this is, sensation alone isn鈥檛 really all that important. When we talk of senses, what we really mean are feelings or perceptions. Otherwise we鈥檇 be operating not much above the level of an amoeba or a plant. The majority of the natural world gets by with just one or two senses 鈥� typically light and touch. A plant that grows to follow the apparent motion of the sun or the Venus fly-trap closing over an insect is merely reacting mechanically to a stimulus.

鈥淰ision could be viewed as one sense, or four, or more. The more we study our sense organs, the more senses we appear to have鈥�

We, on the other hand, see light and shade but perceive objects, spaces and people, and their positions. We hear sounds, but we perceive voices or music or approaching traffic. We taste and smell a complex mixture of chemical signals, but we perceive the mix as ice cream or an orange or a steak. Perception is the 鈥渁dded value鈥� that the organised brain gives to raw sensory data. Perception goes way beyond the palette of sensations and involves memory, early experiences and higher-level processing.

What you hear, for example, is not just a simple sum of the sounds collected by each ear, but a bigger picture. Various processes come into play, some of which allow the brain to tell the direction of the noise. Even more complex processes enable us to screen out one sound when attending to another. In the well-known 鈥渃ocktail party phenomenon鈥�, for example, we ignore all extraneous sounds while taking part in a conversation, but can quickly switch focus if someone else mentions our name. The implication is that we were always 鈥渓istening鈥� to ambient sound but not always 鈥渉earing鈥� it, except when it suddenly becomes meaningful. Our perception goes far beyond the bare sensation.

Higher animals only have to solve one general survival problem in life when encountering an object 鈥� should I eat it, run away from it or mate with it? In making this decision they get ample help from everything they gather from this new experience and previous similar ones. But more primitive animals, with more limited neural equipment, get easily fooled by brightly coloured flowers, or adversaries who can suddenly swell in size, have markings that look like eyes or smell of something unrelated, not to mention all the other tricks evolution has learned to play. A highly perceptive animal is not so much at the mercy of its primitive senses.

The bottom line is that we make a mistake in concentrating on senses, and even in arguing about how many there are. Perception is what matters, and sensation is what accompanies it.

For humans there are other everyday implications of all this. One is in our judgement of size. Consistency in our world view stems from the fact that objects do not usually change size over short periods of time. So for an object that we are familiar with, like a car, the larger it appears, the closer to us we perceive it to be. Though the image we sense is small, we 鈥渒now鈥� the object is big. But we can make mistakes. Clouds can be any shape and size, so their distance is hard to judge. Trains are familiar but most of us don鈥檛 realise just how big they are, and so we misjudge their speed and how far away they are, which leads to around 3000 accidents annually in the US alone. We don鈥檛 solve these problems by internally agonising over which senses are involved or how many senses, but by making a perceptual whole out of it. That is a higher brain function.

Take the strange case of synaesthesia, a mixing of the senses. The most commonly reported forms are experiencing sounds, letters, numbers or words as colours. Synaesthesia is highly developed in some individuals, who were until quite recently dismissed as raving fantasists and sometimes even misdiagnosed as schizophrenic. They may speak of an aroma鈥檚 texture or the taste of different letters of the alphabet. It may be possible to 鈥渉ear鈥� the taste of a peach or 鈥渇eel鈥� a colour. What this tells us is that the senses are less than primary, and that perception is what we really get.

Quite possibly, the brain is set up to do exactly this sort of 鈥渟ense-mixing鈥� as part of the road to perception. There is growing evidence that crosstalk in the brain between different sensory areas mixes up things more than we might imagine. We may spot or recognise objects more easily if we hear a relevant sound at the same time. We may even believe we鈥檝e heard something different if we are fooled into lip-reading something at odds with what is spoken. Ask any migraine sufferer about how a scent can trigger pain. Possibly we all have this facility to a greater or lesser extent, which is why minor chords are 鈥渟ad鈥� and blues music is 鈥渂lue鈥� (an interesting use of language in this context) and food can taste 鈥渟harp鈥�.

Of course, none of this is helped by confusion of nomenclature. Some things commonly labelled a 鈥渟ense鈥� are no such thing 鈥� a sense of loss, having a 鈥渟ixth sense鈥� 鈥� but perhaps the circadian rhythm system should be included. Or is that part of perception rather than a sense? The table on this page tries to bring together the cellular and other definitions of senses into some sort of framework. Doubtless it is flawed, and partial, and open to debate. If anything, it is incomplete. Though in the end, it may not matter at all.

And so, there are at least 21 senses and possibly more. But they could be a distraction. Would we do ourselves a favour by forgetting them, and concentrating on perceptions? As usual, science is fated to challenge everyday beliefs and appear counter-intuitive. We are acutely aware of our vision, smell, touch, so to say they don鈥檛 matter initially seems daft. But senses may one day be consigned to the scientific dustbin, along with spontaneous generation, phlogiston and instantaneous events. It鈥檚 just common sense, really.

It soon became clear to me that everyone regards the Web as essentially a
public service, available as of right, like fresh air, and that anyone who
constructs Web sites is seen as having vast amounts of free time. Did I realise?
No, not me. I鈥檓 far too stupid. Witness three phone calls just after the guide
came out.

The Rev August Personage: 鈥淚 read your guide and I鈥檓 using it to
construct a Church News Web. Could you have a look and maybe tinker with it a
产颈迟?鈥�

Me (in a moment of insanity): 鈥淥f course!鈥�

I spent a full two days, or their equivalent in the dead of night, beating
the thing into shape, although it wasn鈥檛 a bad effort to start with, and I felt
my reward would be in heaven. Not so the next time.

Harry Parry, of Parry, Lemming & Bender, Lawyers: 鈥淚 read your
guide and using it I鈥檝e constructed a PLB Legal News Web. Could you have a look
at it and maybe tinker . . . ?鈥�

Me (not so daft this time): 鈥淣ot a chance!鈥�

HP: 鈥淏ut my friend the Rev Personage says you did him a similar
蹿补惫辞耻谤.鈥�

Me: 鈥淗e doesn鈥檛 charge 拢50 an hour.鈥�

HP: 鈥淲e charge 拢100 an hour.鈥�

Me: 鈥淪o do I, all of a sudden.鈥�

HP: 鈥淵ou can鈥檛 equate the learned legal profession with a bit of
doodling. I mean, where would we all be if amateurs charged the same as
辫谤辞蹿别蝉蝉颈辞苍补濒蝉?鈥�

Me: 鈥淔urther up the world golf rankings. Look, call up an Internet
design consultancy. Then get back to me with an apology and half their
蹿别别蝉.鈥�

HP: 鈥淚 think you鈥檙e being unreasonable.鈥�

Me: 鈥淚s that a professional opinion?鈥�

HP: 鈥淣o, we charge for those. Ah! You can鈥檛 get exams in Webbery so
it鈥檚 just a hobby, right?鈥� . . . Ring ring.

Gary Jarry of The Action Group for the Unemployed and Otherwise Not
Busy: 鈥淚 read your excellent guide and I鈥檝e constructed a TAGUONB Benefits
Web Site. Could you . . . ?鈥�

Me: (less daft by the minute but still with a social conscience)
鈥淚鈥檇 love to help, but if I acceded to all these requests I鈥檇 never earn a
濒颈惫颈苍驳.鈥�

GJ: 鈥淎 lot of people are in that situation.鈥�

Me: 鈥淣ot by virtue of their expertise.鈥�

GJ: 鈥淏ut our chaplain, Rev Personage 鈥︹��

Me: 鈥淲ith whom I鈥檇 like a word. Seriously, there are any number of
people who will be happy to help you. There are even free courses on it.

GJ: 鈥淵es, but I鈥檝e already done it. I just want you to look at it
and say it鈥檚 fine.鈥�

Me: 鈥淚t鈥檒l be better than 90 per cent of the dross out there,
especially home pages from American families who insist on providing full-colour
JPEGs of the entire clan in a Jacuzzi and a list of what they have for dinner
each night.鈥�

GJ: 鈥淪o, you refuse to spend your publicly funded time on a worthy
肠补耻蝉别?鈥�

Me: 鈥淚鈥檓 not publicly funded to do this. I do it in my spare bedroom
with a PC I bought from my pocket money. Try the council.鈥�

GJ: 鈥淚 did. They said talk to you since you鈥檝e given everyone these
grand ideas.鈥�

Me: 鈥淣ice one. Why don鈥檛 you ask your service provider. Maybe
they鈥檒l do you a freebie.鈥�

GJ: 鈥淲hat鈥檚 a service provider?鈥�

So when the book comes out, I鈥檓 expecting goodness knows how many e-mails
requesting 鈥渁 quick look at the Web site I did after Chapter 5鈥�. Would any of
these people buy a cookery book then phone asking the author to pop around and
taste their soup?

I鈥檓 setting up an e-mail responder that says: 鈥淭hank you for your
communication. I鈥檓 glad you have derived pleasure and occupation from my humble
publication. If you divide the money I will make by the time that I spent
writing it, I got 3p an hour. Kindly lodge a protest with
http://www.open.gov.uk at this manifest exploitation and do not add to the
problem. Alternatively, please feel free to come round and dig my garden.鈥�

For non-British readers, a few words of explanation. The Westminster Parliament, or at least the lower house, known somewhat patronisingly as the Commons, operates by virtue of Members of Parliament being invited to say their piece by the Speaker, that member having 鈥渃aught the Speaker鈥檚 eye鈥�. This is achieved in various ways, chiefly by an MP letting the Speaker know beforehand that he or she wishes to speak, or by members standing up, or, on occasions, and I鈥檓 not inventing this, putting on a collapsible top-hat brought for the purpose. Members refer to other MPs not by name, but by a variety of formulas, such as 鈥渢he Honourable Member for Chorlton-cum-Hardy鈥� or 鈥渢he Honourable Lady鈥� or 鈥渕y Right Honourable friend鈥� (if they鈥檙e on the same side) or some similar usage. The whole emphasis is on politeness. Likewise, no MP is ever allowed to accuse another of lying: 鈥渇abricating terminological inexactitudes鈥� or 鈥渂eing economical with the facts鈥� are two favourite ways round this. The Government and Opposition benches are more than two sword-lengths apart to prevent fatalities. Such is the Mother of Parliaments, the model and creator of many other parliaments.

The key to all this is how much respect the Speaker can command. For the first time ever, the office is held by a female, and a redoubtable one at that, the universally respected Right Honourable Betty Boothroyd, the parliamentary representative for West Bromwich West. She controls debates and sets the tenor for the world鈥檚 most sophisticated debating process. Still with me? Good.

Recently, one of her playgroup had the temerity to hold up a graph or chart of some sort while dilating on a point of interest, and got right-honourably ticked off for it. 鈥淭he Hon Gentleman should be articulate enough to do without visual aids,鈥� she ruled, or words to that effect.

But why? One of the things which has always struck me as anachronistic, nay, archaic about the legislative assemblies of the late 20th century, is that they do not use visual aids. Parliamentarians, senators, deputies and their like have to listen 鈥� just listen 鈥� to each other, without the benefit of visual stimulus other than the sight of the member currently upright and the television monitors which they use to check that they are in the shot just in case their constituents are watching.

But how much better it would be if MPs could use the full range of presentation technology available. The Hon Member for Dribblethwaite, or the Minister for Welsh Cricket Pitches could, using her infrared handset, call up images on the end-of-chamber screen from a file she had previously loaded onto the central database. The Chancellor of the Exchequer could illuminate (and, let鈥檚 face it, cheer up) any Budget speech by reference to histograms, line graphs and pie charts showing the full measure of his beneficence, and in 256 colours. The Opposition could grab those images, run them through their party computer (like the one bought by Ken Livingstone, Labour representative for Brent East, using the money he made on TV cheese commercials) and represent them in a different light (鈥淚s the Rt Hon Gentleman aware that if he makes his y-axis linear instead of logarithmic, the Public Sector Borrowing Requirement is off the end of the scale?鈥�). Backbenchers would be able to sit with their laptops composing the bullet points of the intervention they are about to make and flashing them up on the screen so that everybody gets the message. Records could be published as hypertext.

Even better, with fully-networked terminals, conferencing and video capture, our legislators would never have to attend Parliament at all, but could sit in carrels in their constituencies, watching, hearing and contributing to debates and select committee sessions, registering their votes electronically when asked. No more silliness, as we have in Britain, about tellers counting heads passing through lobbies, like so many sheep. The Speaker could simply consult the displayed bar charts and announce: 鈥淭he ayes have it.鈥� And indeed the eyes would have it. Members could even register their votes beforehand, like forward-buy calls on the stock market, since they all know how they鈥檙e going to vote anyway. As if anyone was swayed by the logic of reasoned argument anyway. Not that this proposed system does away with the cut-and-thrust of debate, it simply moves it to a higher plane where pretty words are combined with, and reinforced by, prettier pictures.

But instead, the convenient fiction is maintained that information is all about verbal articulation and that no picture is worth any words. The strange thing is, every politician knows about the power of the diagram. Those who operate a second string in the commercial environment would no more consider making a business presentation without visuals than run naked through the Lobby.

This system would have the additional benefit of creating new jobs. Legislators wouldn鈥檛 just consult 鈥渞esearchers鈥�, employ 鈥渟pin doctors鈥� and hire 鈥渟tyle consultants鈥�. They would need technically adept and visually literate computer graphics jockeys with the requisite arithmetic skills. Watch the sudden increase in spending on the software industry, cash for computers in schools and a re-emphasis on the maths curriculum. The icon-to-word ratio would skyrocket and we would have far less silliness about how our children are being turned into square-eyed joystick junkies. At least the kids know how to do it.

Instead of which we have Godwottery, humbug and a refusal to join the 20th century. Which is rather like saying to Michel-angelo 鈥淒on鈥檛 bother painting the Sistine Chapel. Just tell me about it.鈥�