Question 13: _oo_oo_oo What colour provides the solution? It's very intelligent.

Why does the answer have to be "blue"? Maybe I've read it wrong, but to me, the sentence "A Hooloovoo is a superintelligent shade of the colour blue" implies that "A Hooloovoo" can actually be classified as a colour. Of course, I've just realised that the word "is" may be a little ambiguous here. Was DNA saying that a Hooloovoo is actually the shade alone, and has no other physical presence (as I assumed), or is he saying that a Hooloovoo is some (undefined) physical entity, whose colour just happens to be a superintelligent shade of blue? The latter interpretation bothers me, because of the word "(undefined)". I think that if the Hooloovoo consisted of anything other than the colour, Douglas would have described it more completely.

I think the bear question and the golf question were great - more of the same, please! And thanks for the Joke Warfare picture, I laughed out loud just looking at it. I can actually hear the soldiers' voices in my head, barking out those staccato phrases in German, understanding nothing. I don't suppose you happen to have the actual German text used for the joke, do you? I'd love to know what it was. It sounded plausible; something like "Why is a xxx like a xxx?" I think...

I didn't learn a lot this time, except that there are 50,000,000,000 entries on bloody Monty on the web, and they all go on about Churchill's "In victory unbearable" comment but don't list any quotes from Monty himself (except the one that Mark found, obviously... :-<) I eagerly await the answers so I can be put out of my misery. I'll try another search engine today...

More later,

Mike

Dear Martin,

Barbie and the Hooloovoo Aha! At last, we disagree :-)

Sorry, but your argument is just not valid in my book. The relationship between Hooloovoo and Blue is one of progressive inclusion: "A Hooloovoo is a shade" (AXIOMATIC) "A shade is a colour" (INCLUSION of the concept "shade" WITHIN the concept "colour") Therefore "A Hooloovoo is a colour". You can only disagree with this argument if you are willing to believe that there are things that can be "shades of a colour" without being "a colour" (is that the source of our disagreement?). Trying the same argument with the barbie example, we would fall at the first fence: You cannot say that "Barbie" is a shade - though she may possess a shade, as an ATTRIBUTE: To use currently-fashionable software design language, the "barbie::shade" relationship is one of the "has-a", not the "is-a" type (strictly speaking, it's one of aggregation, rather than inheritance). Therefore your analogy is false. I don't think the answer "Blue" is actually wrong. I just think that "Hooloovoo" should also be allowed.

By the way, for the record, I think that it's quite acceptable for a question to use the phrase "provides the answer" when it actually means "is the answer" (maybe because of my crossword puzzle enthusiasm) - and that's what I assumed you were doing. If you are going to argue that the answer "Hooloovoo" is precluded by the word "provides" because it is too direct, then you may possibly have a point, but I still prefer my logic...

German Joke

Phew, that was a close one! I nearly got joked to death.

Monty Python in General

Yes I thought it was over-rated, too. But mainly because of the lack of quantity, not quality. I think there is a small number of Python sketches that are very funny (some of these are no longer at all funny because they've been done to death, e.g. the Cheese Shop Sketch), and they were padded out by a load of infantile dross. At its best, I rate it very highly, but on average it doesn't compare to true comedy writing.

One thing that always annoys me is that people refer to this kind of thing as "schoolboy humour" as if that's an automatic slant. What's particularly bad about schoolboy humour? Some schoolboys are quite witty and not at all infantile. If people mean "infantile" or "immature", these words have been custom-designed for their purpose and should be used.

Coining new phrases like "schoolboy humour" is a dangerous way to use metaphors, because, as in this case, it leads to "package-deals of evaulation". People see the phrase or hear it, and understand that it is meant to be taken as a negative comment (or positive, depending on the phrase), and the result is a form of collectivism (that ancient attitude from which racism springs), in which the positive attributes (however rare) are ignored and the judgment is made on the entire concept without further analysis. This is why I took so much care to explain above how my opinion of Monty Python on average differed from my opinion of certain highlights within it - which is exactly the kind of careful thinking that many people are evading when they dismiss an entire complex phenomenon with words like "schoolboy humour", "nerd", "jock", "bimbo", "yuppie", "hippie", "pseudo-intellectualism", "namby-pamby lefty" (in the case of a left-winger of high integrity), "fascist" (in the case of a good honest Tory) etc. Yes, I know you never actually said "schoolboy humour", and I understand that your judgment was not made in the sweeping manner I have suggested, but I thought the comment was worth making anyway.

While I'm in a review mode, the Python movies should be mentioned:

And Now For Something Completely Different...

Forget it, this is the same as the TV series

The Holy Grail

Mixed reactions, but generally good. Plenty of great surreal play-acting (the Knights of Ni, the wedding banquet, Tim the Wizard, the rabbit, and especially Cleese as a Frenchman), but also some genuinely funny satire, e.g. "Come and see the violence inherent in the system! Help! Help! I'm being repressed!" Apallingly unsatisfying ending. I know it's anarchic, but couldn't they have finished the bloody story??

Life Of Brian

What can I say? The ultimate irreverent satire. Should be in everyone's video collection. Perhaps unsurprisingly, many Americans think it's the worst film they made. "I'm Brian and so's my wife!", the suicide squad, "Romanes Ite Domum (people called Romans, they go the house?)", "You jammy bastard!", "Bloody jailer's pet", "Worse? How could it be any worse? Jehovah! Jehovah!", "Well what kind of chance does that give me? All right, I AM the Messiah! Now..." I could go on and on all morning, which shows how memorable I found this film. Yes, it's my favourite Python movie. Oh yes, and the classic closing song...

The Meaning Of Life

I find this irritating, but I've never been sure exactly why. Maybe its the clumsy attempt to return to a kind of quasi-sketch format, while attempting to hold it all together (mainly with sex and filth - not that I'm a prude, but too much of it is still too much to be funny any more). For me the funniest bit is the "Supporting Feature" (Crimson Permanent Assurance company), where office workers become pirates - but then, I'm a Terry Gilliam fan - which you probably disapprove of, as he's into fantasies...

:-) Oops, got carried away again, must go.

Regards

Mike

Hi Martin,

Mullet

Hmm.. No I never had one. I know what you mean about the word being a recent invention. I did *perm* my hair once, just to see what it was like. Unfortunately my timing was atrocious. The bloody thing was just halfway through growing out during my graduation ceremony in 1986, and my photo therefore shows an unruly semi-curly mob of rebellious four- micron follicle-spawn. My girlfriend won't have it up on the wall; and neither will I :-)

Graduation photographs are for people with disappointing grades. Discuss.

I could refute this immediately by telling you that I don't even know where my graduation photo is, and I only got a third class honours (which was disappointing for someone with Pure&Applied A level maths (grade A) and Pure&Applied S level maths (grade 1)...). However, I think I know what you are saying. It's like a function that converts a continuous input to a yes/no output. You either got a degree (photo on wall) or you didn't (no photo). The grade becomes something that can be hidden away and not talked about. Of course, at my age and experience level it's quite easy now to say that it's not that important and that what counts is how good you are at your job - but that's really ignoring the fact that when you come out of university, all you have is your degree. Nobody will give you any credit for anything else - unless you are either a friend of the director's son/daughter, or you are an attractive woman (removes tongue from cheek - oops, bad choice of phrase there).

I mean, I don't think that my degree makes any difference to me nowadays in terms of employability. Enough people have taken me on for other prospective employers to look at my CV and think "well, he must have something to offer - these other people can't all be fools". But I could be wrong about this. People often tell me that interviewers are not usually interested in the specific subject you took (unless you are applying for a very specialised position). They just want to know that you have a science degree (if they're after disciplined thinkers), or a humanities degree (if they're after people with good overview skills and creativity, or whatever). Eventually, they can get this information about you from your job history, so the degree itself becomes less relevant.

I've digressed a little, but in answer to the question (which was phrased like an essay question, possibly in an attempt to intimidate, which failed in my case because I never had to answer any of those in my degree...), I think graduation photos are mainly for parents. If not actually kept in the parents' house, then displayed on your own wall for when they come visiting.

Good enough? I really think it's that simple. It's a way for parents to say "look what my offspring have achieved".

Regarding my own poor performance, I like to think that there are three main reasons:

Because of my intense passion for the subject, I already knew everything they tried to teach me in the first year, and coasted through the exams with my eyes closed. Unfortunately, the first year's exams do not count towards the final grade, and when I returned in September 1984 for my second year diet of Analysis, Topology, Operational Analysis, Vector Analysis and Number Theory, I pretty much wet my pants.

I chose the wrong course. Yes, I know everyone uses that excuse, but I believe that I had not matured enough to look at my choice of subjects in the context of my future plans. I was very tied up in the fun of pure maths, and tended to ignore practical considerations. Had I thought more carefully, I might have chosen Computing, or a combined Computing/Maths degree. My level of knowledge now, some 15 years later, would not have been much affected by this. What would have changed is that I would have got a better job, faster.

I joined the film-making club in my third year, and this coincided with my growing disillusionment with my course and my increased apathy over exams. The two aspects fed off each other, and I ended up skipping lectures to devote my creative energies to what amounted to technologically-enhanced Vaudeville for adolescents (we made comedy films for the students to watch). Of course, there's a lot of stuff about this that I don't regret. For example, I was able to meet people like Michael Palin, Richard Attenborough etc. (we interviewed them at the Southampton Film Festival), and learn some stuff about the media; I also gained some significant people-skills from the socially-active nature of the club's activities.

Of course, I might simply be less intelligent than I let on... :-)

Hi Martin,

excuse the classic quotes on your text, but I feel it is appropriate in this case!

I am good at knowing the answer, asking a strange question and starting things off. But bad at taking criticism or following through with methodical work.

I know someone very similar in this respect. And I'm marrying her in September!

OK, time for a little introspection. I'm good at knowing answers in some areas: Unfortunately, in other areas, I'm only good at *thinking* I know the answer. I'm fairly good at asking strange questions, but much better at giving strange answers, which are fruitful about 1% of the time - but I enjoy the other 99% so much that I speak them out loud anyway. This gives me a reputation for being slightly crazy - except among like-minded people (of whom I probably know about four). I'm good at taking criticism, unless I feel it is unjust, in which case I flip completely the other way and go really, really stubborn (this is invariably the source of any domestic rows I have!)

Methodical work: depends on whether it's something I'm enjoying, really - but I have to say that when I *am* enjoying it, it's 110% perfectly- done. That's not a boast - because it generally takes me twice as long as anyone else to do it, so that's not always an advantage. As my boss said to me once when I worked in Configuration Management (an extremely detail-oriented job): "God, you're anally retentive! Don't get me wrong, that's exactly what we need around here." He said this after I had converted a paper system for cataloguing backup tapes into an Excel spreadsheet. I'm very, very grateful that I no longer have to deal with this kind of tedium - but that doesn't mean I'm no good at it :-)

Eventually I will get a proper job.

I will keep looking out for your name in the media. I think you'd make a brilliant columnist.

Mike

P.S. By the way, your updated version of "Lords Of Cyberspace" is EXCELLENT! It's the best rewrite I've seen you do. Much tidier, and every point expressed succinctly. I agree with every word, though I have to say that I'm OK with background images, as long as they are very faint and very quick to load. There's a good example of this on the World Of Dawkins page [http://www.world-of-dawkins.com/]; a faint embossed image of a DNA helix running down the page, very nice, only just visible, not at all intrusive, and it doesn't take too long to load. Anyway, congrats again, good job.

Colours and shades:

ensuring that I knew what a Hooloovoo was That's fair enough - but in that case, you phrased the question incorrectly. I think it should have read: _oo_oo_oo (very intelligent) What primary colour provides the answer?

I'm not bothered about whether you gave me a quiz point or not, I'm bothered about the meaning behind the question, and I'm still not satisfied that I fully understand your point of view. I suspect - though I may be wrong - that we have interpreted the original quote in different ways. Here's my hypothesis: Quote: "A Hooloovoo is a super-intelligent shade of the colour blue." My Interpretation: There exists a type of being known as a "Hooloovoo", and there exists a shade of the colour blue that is super-intelligent. These two are identical elements of reality, one and the same entity. Your interpretation: There exists a type of being known as a "Hooloovoo", and the colour of the light that it emits may be described as "a super-intelligent shade of the colour blue". The problem would arise entirely from the word is, which is read differently in each case. Does this help clear things up? Am I right? If so, then please ignore most of what follows, as it is empty rhetoric. If not, see below!

"Colours are an arbitrarily bordered set of distinct frequencies of electromagnetic radiation, the pure tones. The notes. Shades are the chords. Whereas in chords of music harmonics are important in shades the subtle differences come from the mixtures of other frequencies." Are you saying that shades are not colours? If you are, then I disagree. A colour is any sensation involving different relative amounts of stimulation of the cone cells in the retina. This includes not only red, green and blue, but also yellow, black, white, grey, pink, orange, turquoise, purple and all the different shades of these that you could imagine. The musical analogy is very good, but note that both pure tones and chords may be described as sound - and (key point here) this is the word that I would say is analogous to the word colour. (Well, almost: Actually, I would describe black as a colour, but I would not describe silence as a sound, so that's the one exception.) Yellow is a colour, as I'm sure you would agree, so by your argument above, it should be analogous to a note rather than a chord. So what is its 'note'? It's 'frequency'? Of course, it has none. Yellow is the colour perceived when roughly equal amounts of electromagnetic radiation are stimulating our 'red' and 'green' cone cells, and low amounts, or none, are stimulating the 'blue' cone cells. You could say the same of orange, or pink, or brown, or purple, or peach, or turquoise... the number of visual experiences that would be described as a colour by the majority of people includes a great many that are combinations of different frequencies, and only a small number (three, to be exact) that are pure primary colours.

It's worth noting that the same experience of yellow can result from a range of different physical phenomena. If a monochromatic light source is used, with a frequency that lies between red and green, such that equal amounts of stimulation of the red and green cones occurs, then this is called yellow. However, you can get exactly the same effect by using a mixture of two light sources, one red and one green, in appropriate proportions. An example: consider a "red/green/yellow" LED (light-emitting diode). This actually contains two LEDs, one red and one green. By varying the voltages applied to its terminals, one can obtain red, green, or any shade between them, including yellow. Imagine for a moment that one of these LEDs is mounted in a panel, and next to it a special LED (I don't know whether they exist) that emits yellow light only (i.e. it is truly monochromatic). The first LED is set up to look the same colour to the human eye as the second. Suppose then that an intelligent being of another species were present (give Mulder and Scully a call if you can't find one), that had colour vision, but with different retinal cells to us, so that it could detect yellow, red and green monochromatic light independently (it has a type of cone cell for each). In this situation, a human being would say that the lights were the same colour, but the alien would say they were different colours. All this shows is that the concept of a primary colour is anthropocentric.

All detection of light is a question of spectral analysis - the degree of resolving power and the frequency bands used are not fixed, they can be designed deliberately to an agreed specification, or (as in our case) they can evolve. The word shade surely exists (in this context, anyway) in order to refine the concept of colour - but I think you are misinterpreting this as evidence that they are separate ideas, and that a shade therefore cannot be a colour. My argument is that anything that stimulates the cone cells in the human retina to any specified relative degrees, is a colour. That includes black, white, grey, pink, orange and - yes OK - red, blue and green. We have the word shade so that we can construct sentences in which we compare colours that are so close to each other that we don't have two words for them. For example: "Those curtains are a darker shade of blue than this carpet". This does not mean that the curtains (or the carpet) are not blue! It would be madness to claim that. The word shade is the fine-tuning control of the concept for which the word colour is the coarse control - but shades are still colours, by inclusive definition.

By the way, on a related but irrelevant point: I've never understood people who say "white and black are not colours". To me this is like saying "zero is not a number", or "absolute zero is not a temperature". You can see their point in a way, but, scientifically speaking, their attitude is not a practical one. The source of this problem is that we developed the idea of black, white and colour in ancient times, before anything was understood about the physics behind it all. Now that we know the facts, we should have redefined "black" as "a colour with no energy", and "white" as "a colour with equal amounts of red, green and blue energy", so these two should be included in the concept "colour". Unfortunately, ignorance gives the older usage a momentum it should not deserve, and people disagree as a result. I'm sorry for being so pedantic. It's just my nature; if I feel that I've missed a point, I can't rest until I've understood it.

Where is my quiz entry? Guilty! Sorry, I had no time last week, I just didn't get around to it. I'm not going to claim that I have a life and you don't, or anything childish like that - but I do find that my Internet activity runs in cycles. I disappear for a while sometimes - you just have to expect it, I'm afraid. Also, I used to do the quiz at lunch times at work, but now I'm reading The Selfish Gene instead, and I'm afraid that gets priority!

I see the hooloovoo in the same way you do, pure light. It is obvious nonsense that a colour or shade could be superintelligent, but you have to suspend your disbelief for fiction anyway, at least with Douglas Adams you know he wasn't going to take your willingly suspended belief and run off with it and bury it in the garden. Or at least if he did he wouldn't then run around distracting you while you were looking for it.

Yellow light is not just stuff that happens to cause a particular reaction in the cones of our retinas. It is also electromagnetic radiation of a particular frequency, although it is more usually referred to by its wavelength, which I am sure you know is the same thing measured the other way. Think about lasers, they produce pure "notes", whereas regular lightbulbs produce very complex chords, but each with a distinct timbre. Now that has really mixed up the metaphors!

What is a colour? It is a tricky one. I think my grasp of physics is not good enough to be definitive. I would like to play and do some research on it. What would happen if you took a red laser and a blue laser and shone them both on a white target? Would there be perceived mixing of the colour only or would it be possible to take the resulting light out with a prism or two and find new colours being made in addition to the two we input? Real harmonically created tones that could be isolated?

I think it is wrong to talk of three primary colours. That is not the way the universe works. Colour is a measure of wavelength, photons do not come in three colours, they come in infinitely variable, but discrete, colours that range from ELF radio to cosmic rays. The wall next to me is light beige, it absorbs many frequencies and reflects many, the overall net effect is more reflectance than absorption, therefore it appears pale, but with some discrimination in the absorption so that it does not appear simply grey. In one sense colour is simply another name for frequency in Hz or wavelength in metres, with the appropriate lots and lots and itsy-bitsy prefixes. In another sense it is arbitrary.

All human languages have words for red white and black, but some stop there, most have words for yellow and green but orange and pink, purple, peach, cyan, burgundy and taupe are all optional and arbitrary. English is a rich language but I am not sure if I can name as many shades with a distinct word or phrase as even a 256 colour monitor can handle. I never feel any need to use more than high colour for my screen, I am not really aware of more than 65,536 shades. I suppose my colour sensibility lies somewhere between 256 and 65,536. Having said that I find if I take a full colour photograph and save it as a GIF file with 256 colours from an optimized palette it is hard to tell it from the original. My colour perception probably extends into the tens of thousands of shades but my colour vocabulary is much more limited, I am now looking at a weather beaten garden fence and trying to come up with a palette for it. Tough call, lime green airbrushed in the finest mist over a striated base of grey and brown, isolated patches of richer chestnut from the remains of the creosote. If I was to mix a palette for an oil painting I would probably make about twenty shades, if I was to save a photographic image of it I would not consider anything less than 64 colours, more likely 132. I am quite sure a child would just reach for the brown felt tip.

I am not sure how I take the distinction between shades and colours. There is a difference between a single pure laser style single frequency of visible light and say, "warm terracotta" or "buttermilk" which are definitely mixtures of colours, many shades of red, some yellows and a little green, perhaps a little blue, causing an overall lightness but with a distinct warm hue. Shade and colour are different, pure note and chord are different, but I don't think the words match up to the same dichotomy that underlies the physics. I can picture two distinct pure laser beams, both blue, but different shades, both pure colour, both blue, both pure blue. Are they different shades of the same colour, or different colours? My head hurts.

Have you ever done those blobby pictures with hidden patterns in them to test your colour vision? I suppose we would all fail an alien's colour blindness test, if there were aliens with better or comparable colour vision, which is by no means obvious. We think of vision as being very important, but that is just because of the way our bodies work. When we travel as a passenger in a car we have a desire to look out of the window, in contrast a dog wants to put its nose into the passing airstream. Perhaps aliens will greet us by sniffing our crotches and licking our faces.

Martin

Dear Martin,

Sorry, this is a 2,500-word email. I got very carried away this time...

 Colour

The dualism of physics versus physiology

Yellow light is not just stuff that happens to cause a particular reaction in the cones of our retinas. It is also electromagnetic radiation of a particular frequency. I think this is misleading. Yes, there is a range of single 'pure' frequencies of light that we perceive as yellow, but there are other spectra (combinations of red and green wavelengths, for example) that have an identical effect on our retinas. This is because each cone in the retina responds to a 'bell curve' around a central peak wavelength. So, if low-intensity red and green wavelengths are both received at once, the red and green cones will both respond, and if a single yellow wavelength is received, of a frequency that lies within the response curves of both red and green cone cells, then an identical response occurs (given a larger energy level in this case), and in both cases we would see exactly the same yellow light (all other things being equal). The attached diagrams may help to explain this.

Diagram 1

Diagram 2

In each diagram the horizontal axis represents frequency, and the vertical represents energy or sensitivity (loosely - the curves are probably the wrong shape, but they're broadly representative). The solid red and green curves represent the sensitivity of two of the three types of cone cell in the retina, depending upon the frequency of the light.

Diagram 1:

The dotted line would be one example of the spectrum of a 'pure' monochromatic yellow light source, and you can see that this would stimulate the red and the green cones equally.

Diagram 2:

A different spectrum is received, and stimulates the red and green cones equally again, in each case at a lower intensity, but because the peaks coincide with the peaks of sensitivity of the cells, the effect is amplified, and the response is identical to the first case. The colour perceived would be an identical shade of yellow in each case.

I realise that you were saying that yellow could be both a wavelength and a particular reaction, but my point is that it is misleading to focus on the special case in which the light source is monochromatic. Light sources with a single wavelength are rarely found in nature! I agree with your analogy about lasers producing notes and light bulbs producing chords, but only if the notes are pure sine waves. If a note is anything other than a pure sine wave, it ceases to be analogous to a monochromatic light, and becomes more like a spectrum with emission lines in it. By the way, the 'All other things being equal' comment near the beginning was a reference to the fact that our colour perception is relative, and the same spectrum of light placed in two different contexts can look very different. Hence the blue tint when you use a video camera in daylight without setting the 'white balance' correctly. But that is far too long a topic to deserve inclusion here!

"Does physical combination of light produce new frequencies? What would happen if you took a red laser and a blue laser and shone them both on a white target? Would there be perceived mixing of the colour only or would it be possible to take the resulting light out with a prism or two and find new colours being made in addition to the two we input? Real harmonically created tones that could be isolated?" No. Separation using prisms would merely give you the original pure frequencies. If the lasers were diffused enough to be more like discs than tiny dots and the discs overlapped, then the eye would see magenta on the white background, because both blue and red cones would be stimulated, but that is a virtual effect; there is no 'magenta frequency' present in the light.

Do you see, by the way, how hearing and vision differ? In colour vision we have just three types of receptor for three different frequency ranges, but in hearing, the entire cochlea in the inner ear, with its thousands of tiny resonators, can detect an enormously greater number of separate frequencies of sound. In the eye, spectrum-analytical power is sacrificed in favour of spatial resolution (lots of cells but only three types - four if you count the rods too). In the ear, it is the other way around: there are thousands of separate waveband receptors of different frequencies, but only two inputs - the varying pressure in the left and right ears - and in my opinion it is astounding how the brain can work out directional information in sound from such a limited input: there's a Darwinian miracle to counter the religious ones, any day!

Is a primary colour a valid concept?

"I think it is wrong to talk of three primary colours. That is not the way the universe works. Colour is a measure of wavelength, photons do not come in three colours, they come in infinitely variable, but discrete, colours that range from ELF radio to cosmic rays." I agree that we do not speak of primary colours because of any physical property of the universe that makes those particular frequencies special. But there is a good reason to use the term. We have primary colours because those frequencies happen to be the three peak detection frequencies of our colour receptors, and that's why composite colours of light are possible. Composite colours only work because we see colour using a three-band spectrum analyser. If we saw a fairly continuous range of light frequencies (of course there would still be discrete bands, but imagine for a moment that they are as numerous as those detectable by our ears), then composite colour would not even be known to us as a concept. Instead, there would be so much information present for us to perceive, even in a uniform light field, that we might even go around describing different types of light as if they were different shapes! Imagine that! "I don't like the colour of your new car, it's got those four ugly bumps in the middle of its spectrum. Eugh!" :-)

Quick aside: By the way, the printing process is different. Its three primaries are yellow, cyan and magenta. You can see these in the ink reservoirs of your colour inkjet cartridge. This is because pigments work by subtractive composition. White ambient light reflects from the white surface under the pigment, but it has to pass through the pigment as it does so, and the pigment subtracts (absorbs) a particular frequency range from the light. For example, yellow pigment and cyan pigment make green, because yellow pigment removes blue light and cyan pigment removes red light. Presumably, evolution has furnished us with the three primary frequencies it has, because most of the useful knowledge we can gain from the natural world's variation in electromagnetic radiation lies broadly in that range of frequencies and is capable of effective classification using those three narrower bands.

Of course, if lots of things in the natural world emitted, say, microwaves, then we would have evolved sensory organs for detecting them - and there would probably be more than one frequency of microwave receptor cell in our 'microwave eye' in this case, too. But let's stay with normal visible light. Suppose that plants had evolved something other than chlorophyll to do the same job, and it was yellow instead of green. The frequency we currently call 'green' would be a far less important one to us, and no doubt we would be likely to have evolved a different set of receptors in this case. If we had, say, two types of cone cell instead of three, that peaked around the 'yellow' and 'cyan' frequencies, we would be speaking of 'the two primary colours' instead. If this were true, then green would actually be a secondary colour, composed of yellow and cyan! If you doubt this statement's validity, just look at my two diagrams again, but imagine that red and green move to the right and become yellow and cyan respectively (cyan would be to the right of the green position), and that instead of a yellow monochromatic light source, we had a green one. The picture would be just the same, but moved to the right! In our hypothetical two-primary-colour world, televisions and monitors would be using two colours of phosphor instead of three, full-colour computer images would store each pixel in 16 bits instead of 24... the list goes on. The human world would be a slightly different place, but the universe itself - naturally - would not change. Incidentally, I do not know much about colour-blindness, but I would guess that it is some kind of failure of one or two of the three types of cone cell. I wonder whether there is also genetic variation in the peak frequencies of the cone cells? This raises interesting possibilities for that age-old question: "Do you see colours as I do?" - particularly in regard to the adjustment of computer monitors and TVs to suit individual tastes. I'll leave that one for now, though!

Mixing it

I am not sure how I take the distinction between shades and colours. There is a difference between a single pure laser style single frequency of visible light and say, "warm terracotta" or "buttermilk" which are definitely mixtures of colours, many shades of red, some yellows and a little green, perhaps a little blue, causing an overall lightness but with a distinct warm hue. I agree that the two types of light have a different 'feel' to them. However, this is a subjective partitioning of the range of possible input data. You are still making the assumption that all pure colours (as described subjectively) are single wavelengths, and I have shown above that this is not the case. You even use 'some yellows' as an example of colours that contribute to warm terracotta and buttermilk - but yellow is not even a primary colour. In reality, warm terracotta, for example, is a name given to a combination of three primary colours in specific proportions. However, a large range of different types of light could cause us to perceive this colour, because we are reducing the information present in the spectrum when we analyze it with our three anthropocentric frequencies. We name colours for their effects on us, not for their physical nature.

Shade and colour are different, pure note and chord are different, but I don't think the words match up to the same dichotomy that underlies the physics. Actually (this is important!) pure note and chord are not different, they are merely subjective evaluations of a sound's spectrum. Have you ever heard an 'orchestral sample' being used as a note in an early-nineties dance track? That's somewhere between a note and a chord, wouldn't you say? It has a basic frequency, but so many overtones that you'd hardly call it pure. The range between pure sine wave (just the fundamental frequency) and 'white noise' (equal energies of all frequencies) is evenly filled with different possibilities. How would you go about partitioning it into notes and chords? I think that you can only define 'chord' if you are talking about combinations of notes with strong fundamental frequencies. As the notes themselves get more rich in complex overtones, chords composed of these notes become more and more difficult to distinguish from 'noise' (a musician might say they get 'muddy'!) So there's part of the answer. A pure note is not necessarily just a fundamental sine wave, and in the same way, the thing that we might name as a pure yellow might very well be a combination of different frequencies of light. The stuff I've written about the gradual range of change between pure sine waves and white noise, with notes and chords positioned along the line somewhere, sums up very effectively the reason why I feel that your distinction between shade and colour is arbitrary and meaningless.

I still think that the word 'shade' is a very useful one, but I think that it should be used comparatively. In other words, only in situations where there is no other way to describe the difference between two colours except by saying 'they are two different shades'. To me, this still means that it is perfectly acceptable to name any given light spectrum 'a colour' - and you yourself referred to a '256-colour monitor', not a '256-shade' monitor, showing that, at least to some extent, you have accepted this principle. Oh, just before I get to my conclusion, let's look at: I can picture two distinct pure laser beams, both blue, but different shades, both pure colour, both blue, both pure blue. Are they different shades of the same colour, or different colours? My head hurts. To a physicist (or a logician!) they are different colours. To the average person, maybe not. But that's due to the practicalities of everyday life. We are speaking of precise definitions. There are three properties of colour (you must have seen them in graphics software):

Hue (the dominant frequency - this is like the fundamental frequency of a note)

Saturation (How near it is to a pure colour, and how far from a shade of the black-grey-white scale - this is like the degree to which a note has a fundamental frequency, rather than being noise)

Brightness (the amplitude - this is simply like the volume of a sound) In the case you are describing with the blue lasers, if they really are both pure monochromatic laser light of the same frequency, the only variation that is possible is the brightness. If you think you can see two different colours (or shades), you are just seeing two different brightness levels. Of course, I could argue that different brightnesses of the same hue and saturation are in effect different colours, but that could be a very thorny issue, and I'm not sure I want to go there!

My Main Point Starts Here!

If the two lasers are slightly different frequencies, but can both be described as 'blue' then I accept that you could say that they were different shades. However, I don't see any reason to disallow the claim that they are also different colours, while both being 'blue'. There is no paradox here; it's equivalent to saying that two people come from the highlands of a country, but that they are from different altitudes. In this analogy, altitude = colour, blue = the highlands. Highlands/lowlands is a subjective distinction. Most people would agree approximately on the boundary's location, but it would vary slightly. The same happens with colour. Suppose that green = the lowlands. Then you can say that blue and green are different colours (highlands and lowlands are different altitudes), but you are not making a precise definition. You can also say that two highland locations are at different altitudes (two shades of blue are different colours, but both are blue). Note my wording: Two shades of blue are different colours. This is an example of why I consider every shade to be a colour.

Hopefully this massive epistle has explained to you why I think that: ANY uniform visual input may be described as a COLOUR Anything that is a SHADE is also a COLOUR Therefore, although a Hooloovoo is a super-intelligent SHADE of the colour blue, it is also by definition A COLOUR in its own right (because every SHADE is a COLOUR)

Thank you for allowing me one last chance to educate you. I hope I have not been insulting or patronizing (or wrong!) at any point. Actually, writing this piece has helped me to understand my own instincts in terms of the facts, so it's been a useful exercise, whether I have convinced you or not.

Phew

Colour

Thanks for your thanks. I like writing stuff like that. I take your point about the laser frequencies, and in fact I used it as the starting point for my section entitled "My Main Point Starts Here!". I know didn't make it clear that I had understood your original comment, but in fact I had.

Quiz

I love the phonetic alphabet question! It had me totally up the wrong tree; I was looking for a month whose letters matched the items listed - Duh!! I suppose I might have spotted the trick, had I not made the initial disastrous assumption that the country was China... My answer to The Doors question was a fine example of why you should not trust the www completely. Someone out there had the title wrong, and I just copied their bad meme. I'm kicking myself now, because I knew it! I had that album at university, and played it over and over again.

Suggestion for mutual benefit? Would you like me to contribute a cryptic crossword to the site at some stage? They usually take me a few weeks to compile (I'm a busy boy), but I'm quite good at it (honest!) and I love having people solve them, it gives me a kick. Maybe we could achieve symbiosis here? Hey, maybe you could give me a few clues to throw in the mix too - to keep the style nice and varied.

Changes to site

I have some suggestions: The navigation bar on the left currently seems to change font, and sometimes even content (you may have fixed the latter by now, I haven't noticed it recently), depending on which page you are viewing. You could make this more consistent. I haven't been back to your piece "The day the music died" since I first visited it a few weeks ago, but I remember that it had an auto-playing music file (MIDI?). Nothing wrong with the music itself, but the noise caused me some embarrassment, as I was sitting at my desk at work at the time, and had not muted my speakers! I realise this is more my problem than yours, and in fact whenever I surf the web at work now, I'm in the habit of muting. On the other hand, you actually deride auto-playing music files in your tirade against the "Webmasters", so if it is still there, perhaps you could consider removing it, or making it optional. The main Quiz page would be better presented as a table, with Quizzes in one column and their answers in the other. Of course, once you visit a particular quiz you could still have a Prev/Next/Answers nav-link group: I just think the main access page should present all the quizzes in a table, as it's nice and neat. Hope these are useful to you.

Atheists, Church Attendance and Hypocrisy

I've been meaning to write this for a while now. It's quite a short idea, but I think it might be useful to state it: Atheists are more at ease in a church than lapsed church-goers. I have actually come across examples of this, and the reason should be obvious. If you don't believe in God, you are simply entering a place where people conduct meaningless rituals. If you no longer attend church, but (openly or secretly) still believe, then you will be filled with guilt at the thought that God is watching you and saying, "Ah Mr. Bond! I've been expecting you!". Any thoughts on this?

I don't beLIEEEEEEEEEEEEEEEEEVE it!! I came across that lyric in my search, but gave up because it did not contain the word 'gnome'. I'll have to wait and see what the answer is to be enlightened. The suspense is killing me!!

I have a good story about gnomes, which I'll tell you tomorrow (see, I can be cryptic too! :-)

Mike

Hi Martin,

here's a little anecdote for you. I think it illustrates very well how alien a culture can seem, even when it's practically on your doorstep.

When I played in a band for a couple of years, we had a tour round Europe which included an overnight trip from Germany into the Czech Republic. Shortly after our minibus crossed the border at around 3am, we began to notice a very odd phenomenon. By the roadside at regular intervals could be found little miniature garden centres, all lit up and open at that stupid hour, and every one had on display at least fifty garden gnomes of various sizes! We checked with each other - and no, none of us had taken any drugs, the bizarre sight was actually real. We quickly became hysterical as each new corner revealed yet another industrious Czech, up in the wee small hours hoping to sell his gnomes to some unspecified night prowler. Every time another appeared, the bus rang to the shout of 'GNOMES!'. We even stopped at one shop and had a quick look around to make sure they really were open - which they were, inexplicably - but, none of us being able to speak any Czech, we were unfortunately left none the wiser about their surreal marketing strategy.

Eventually, another element was added to the game, as larger settlements began to appear, populated almost entirely by scantily-clad over-painted ladies, who, on the occasions when we slowed down, were drawn to our windows like wasps to a pint of summer ale. The game now became more complex; not only was the objective to be the first to cry out, but one had to use the right word: either 'GNOMES!' or 'WHORES!'.

Of course, the reason for the latter's presence was a lot clearer to us, the route being one used by many lorry drivers, but the little men of painted clay remained an enigma. A few days later, we were able to ask our hosts in Slovakia what was going on, and they laughed, telling us that the Germans were very fond of garden gnomes, and knew they could get them at rock-bottom prices across the border in the Czech republic - which apparently they were in the habit of doing, although I'm still not quite clear why they had to do it at night. Perhaps smuggling gnomes into Germany is illegal or something - but I can think of far more dignified crimes to be caught at! I'll try and dig out a picture of the gnomes to send to you - I think I've still got one somewhere.

Mike

Franc Tremblay

In my opinion, he's just trying to set the record for the longest cyberbelch. Every time you present well-reasoned argument, he throws it back in your face by claiming contradictions that don't exist, writing gibberish about his own views, re-stating cases that have already reached stalemate, needlessly quoting huge portions of your text to the detriment of bandwidth, densely missing the point by light years, turning linguistic molehills into vast mountain ranges of false refutation ('doubt' vs. 'question', for example), gratuitously using personal abuse with the sole intention of starting a flame war...

Actually, he's right. Delete the little arsehole's posts already.

PLEASE!

Then we can get on with some reasonable discussion without being distracted by overblown, pretentious adolescents with verbal diarrhoea who think that knowing a load of philosophical terms entitles them to an excess of arrogance.

I was going to say, delete all his posts that contain personal attacks or emotional language - but then I realised that this amounts to the same thing. I was also going to post this message to the Forum, but I decided against it. I think plenty has been said there already and it would do no good to anyone.

Dear Martin,

Sorry about my outburst in my other email. Maybe you shouldn't delete M. Tremblay's posts - that would remove the evidence, which at least shows his true colours.

I've calmed down a little now, and I went and had a look at Franc's profile on Suite101. He's a 23-year-old Objectivist, which to me explains most of it. I was quite similar in my views at his age, having read Ayn Rand's works over and over again. Since then, I've absorbed a few more ideas from different quarters, and while I don't deny that Objectivism is under-rated and deserves more attention, I have also found that it doesn't cover everything that I want to think about. Without wishing to sound supercilious (though it's probably unavoidable), I do think that Franc has yet to take this step and overcome his evangelistic fervour. When I said that Franc's credentials only explained most of it, I meant that I've never met an Objectivist with such a belligerent attitude (though some did have leanings in that direction). My intuition is that it's personal against you, Martin - perhaps because of your evident left-wing politics. Then again, maybe it's because he's Canadian. They certainly have a reputation for weirdness...

Do you get many threads like that one? Most of your contributors seem quite well-balanced, and it's the first time I've seen anything like it on the Forum.

Mike

P.S. Interestingly, Francois says the following on his web site:

Now, I am not saying that you must absolutely believe all the arguments that I have presented. The area of strong-atheism is still in its infancy and full of speculations. Far from me the idea of pretending to absolute truth (such a thing cannot exist for us, of course).

If he thinks this way, why did he make those comments about 'seeing absolute truth through the use of reason'?

"Please can anybody tell me how fast a car weighing 1000Kg, with neutral lift, would have to travel around inside a vertical loop of road 1 km in circumference without coming off upside down. If you feel like giving other comparative figures please feel free. Please explain your answer in a way I, a man who stopped learning about physics at 14, can understand."

The hardest thing about this question is explaining the answer properly! Here goes... OK, first of all the mass of the car is not relevant. It could be a 1kg remote-controlled model, it would still have to go at the same speed to avoid coming off. Of course, we are ignoring air resistance as well as lift, I assume...

The car is at the most risk at the very top of the loop, as I'm sure is clear. At this point there are two main forces acting upon it. One is the Earth's gravity, and the other is the Normal Reaction Force produced by the contact with the loop's surface. The effect of gravity is to induce an acceleration of g (about 9.81) metres per second per second, acting downwards at all times, and this does not depend upon speed, mass or direction. The effect of the Normal Force is to counter the tendency of the car to continue in a straight line, and it will do this whatever the speed, up to the stress limits of the material the loop is made from - at which point it's brown trousers time :-) This means that the loop constrains the car's motion to a circle, but in order for this to happen there must be an inward acceleration, and there is a well-known formula for calculating this (I could go into the calculus used to derive it, but I don't think you want that!)

a = (v^2)/r metres per second per second

where v is the speed in metres per second and r is the radius of the circle in metres. In order for the car to remain safely upside-down on the track, the outward (upward) acceleration due to its circular path must equal or exceed the downward acceleration due to gravity. Therefore,

a >= g

So (v^2)/r >= g

So the exact speed below which the car would come off is given by: (v^2)/r = g v^2 = gr v = sqrt (gr)

In this instance, the circle's circumference is 1km, or 1000m, so r = 1000/(2 * pi), and we know g = 9.81 (approx),

so: v = sqrt ( 9.81 * 1000 / (2 * pi) )

This comes to 39.5 metres per second, which is 142kph (about 89mph)

By the way, I don't think I ever want to accept a lift from you :-)

Algebraic thoughts

Iceland + Wales = Portugal

England - Wales= Portugal

Portugal + Wales = Andorra

Andorra - England = Iceland

England x Iceland = ?

Iceland. England and Andorra both have two land boundaries, so represent 2. Portugal and Wales both have a single land boundary and so represent 1, being an island Iceland obviously represents 0.

This is interesting, Martin. I don't know whether you allowed my answer, but I'd have no objections at losing a mark for this one, as I hadn't spotted the 'land boundaries' factor. But did you realise that it was possible to get the answer 'Iceland' by pure algebra, as if the country names were simply variables in equations? That's how I did it. In order to make the question reliant upon knowledge of geography, you could simply remove the second reference to Iceland, i.e.

Iceland + Wales = Portugal

England - Wales= Portugal

Portugal + Wales = Andorra

England x Iceland = ?

Regards,

Mike

See my other email; you might understand it better. Also, the answer above is assuming r = 1km, but you said the *circumference* was 1km, so it's wrong.

I got 142kph, meaning it could perhaps be done in a fast sports car - remembering that you'd need extra power to maintain that speed or greater, all the way to the top of the loop. I'm not sure how cars perform when climbing vertical inclines and worse(!)

Hi Martin

On the subject of the car-in-the-loop: Thought you might like to know this: a colleague of mine tells me that, in theory, even without the banned 'ground effect' modification, a formula one car could drive upside-down under a horizontal surface, because of its ground-hugging aerodynamics. I feel that this sheds new light on your 'barrel roll' comment!! Regards,

Mike