There is one very simple answer that those who accept the principles of astrology give to sceptics who condemn it as a load of mumbo-jumbo: don't look at the stars for an explanation, go to the coast and look at the sea.
The massive power of waves and the tides that cause them are, it is universally accepted, a direct consequence of the gravitational influences of the Moon and the Sun upon Earth. We also know that the Moon sometimes determines animal behaviour and has long been linked with aspects of our lives as diverse as a women's menstrual cycle and mental disturbance, hence the word lunatic.
Is it, astrologists argue, therefore completely impossible that the other planets also exert influences on our lives and personalities, to greater or lesser degrees and in varying combinations? And that, having been around in various forms since the ancient Babylonians first began to describe celestial omens 4,000 years ago, astrology deserves more respect than the derision commonly accorded it by the rational scientists and the established churches.
Astrologists were forced on to the defensive once again yesterday after the publication of a German-Danish study of more than 15,000 people - the largest of its kind - which concluded "in no cases did date of birth relate to individual difference in personality or general intelligence". There was "no support" for a link between date of birth and the "Sun signs", the report said, and there was probably "more truth in a comic strip".
"It is the same old story," sighed Adam Fronteras, a former president of the British Astrological and Psychic Society (BAPS) and a regular broadcaster and writer on astrology and other psychic matters. "We've had these reports many times before. Because such research tests one or two factors only, it's a bit like judging a work of art using only one or two colours or a book by reading two pages. Astrology is much more complex than that."
Marlene Houghton, an astrologer for more than 30 years, puts it another way. "Astrology is a metaphysical doctrine, not a science, and cannot be easily judged by the narrow instrument that is science."
So what is astrology? It should never be confused with astronomy, the study of the planets and stars and whose practitioners, such as Sir Patrick Moore, are among the loudest critics of astrology. Astrology is seen by its advocates as a far more complex subject than the broad brush of the "Sun sign" astrology of newspaper columns and television pundits, where personality traits and predictive forecasts are ascribed to the 12 signs of the Zodiac in which people are born.
And it is not, stresses Christine Chalklin, the director of the Astrological School of the BAPS, a belief system. "I get very annoyed when people ask me why I believe in astrology," she said. "It is more like a language which is there to decipher and understand and to use during our lives. And it can have immense value."
Although there are many different sources of astrology, most modern Western "horoscopic" astrology dates from Hellenistic Egypt around 100BC and is different from, say, Hindu or Chinese astrology, although all share the same core practices.
Western astrologers base their study of a person on the calculation of their horoscope (a word derived from the ancient Greek) or "natal chart" - the positions of some of the planets, the Sun and the Moon - at the precise time of birth. These are plotted against the Zodiac (from the Greek word zoon, meaning animal), an imaginary belt in the heavens which includes the Sun's path (the ecliptic) and the apparent paths of the Moon, and the planets Mercury, Venus, Mars, Jupiter and Saturn. It is divided into 12 parts, each of 30 degrees and named according to one of the constellations - Aries, Taurus, etc.
The astrological year thus begins when the Sun moves into Aries on about 20 March and ends when it moves out of Pisces. It is from this basic formula that all astrology is derived: Aries represents the first sign of the Zodiac and is therefore associated with all things youthful and springlike, while Pisces is the sign of ageing and mysticism.
Aries is one of the three fire signs - the others are Leo and Sagittarius - while the remainder are either earth, air or water signs and, it is believed, people who are born to those signs share some of the characteristics of those elements. People born as a Taurus, the sign of the bull, being an Earth sign, are commonly considered to be solid, practical and predictable - but with an occasional bull-like tendency to charge into things.
But while the Sun determines the principal sign, the positions of the Moon and the other planets in the different signs complete the full natal chart, creating a complex and inter-related web which can determine many character traits. To this can be added other factors - the Moon changes signs every two or three days, Saturn every 18 months or so - which can exert influences on our lives, but which are mitigated by where the other planets are at the time and how they relate to each other.
Further aspects come into play. People born at the start of the astrological periods will share some characteristics of the preceding sign, while someone born in the Sun sign of Taurus, but with most of their other planets in, for instance, Gemini, may not be a typical Taurean.
It is this sophisticated and complicated pattern, Mr Fronteras said, that astrologers study and interpret to determine the character of a person and what might be in store for them. "Much of what most people know about astrology is based upon the Sun sign astrology, and that is only about 10 per cent of the whole picture," Mr Fronteras said. As a broadcaster and columnist himself, he is reluctant to criticise the multimillion-pound industry that has grown up around popular Sun sign astrology and those who perpetuate it, such as Russell Grant on television or Jonathan Cainer, reportedly the highest-paid writer on the Daily Mail.
"It's a shop window, that gets people through the doors. It's just a snapshot of what people are about." Even Grant attacked the latest research yesterday for failing to distinguish between "popular" and "proper" astrology, inadvertently condemning the commercialisation of the craft he has been most responsible for creating.
But is there any scientific basis for astrology? Most scientists, such as Sir Patrick, dismiss it as pseudo-science. Recently, however, some heads have been put above the parapet. In the late 1970s, Michel Gauquelin, a French statistician and psychologist, suggested that there were statistical links between birth dates and certain professions. Two years ago, Percy Seymour, a former astronomy lecturer at Plymouth University and a member of the Royal Astronomical Society, published a book arguing that, while he did not believe in horoscopes, the movement of the Sun, Moon and various planets certainly held an influence over us.
While most scientists poured scorn on his opinions, a very few accept that there is more research to be done. Until there is positive evidence one way or the other, the nation is likely to remain addicted to its newspaper astrology pundits and its dial-a-horoscope chatlines.
Belatedly, this writer must declare an interest. I have always been intrigued by astrology and once co-wrote a book on the subject with my best friend, who was an astrologer at the time. In retrospect, it wasn't a terrific piece of work: since he's a Cancerian and I'm a Leo, two of the least compatible signs, it was a working relationship mostly characterised by argument: as a crab, his tactic was to scuttle in sideways and snap, while I, the lion, roared around a lot.
We never got it published, but we learnt a lot about each other. I've never seen astrology as a prop or a belief system but, as Ms Chalklin says, simply a tool to better understand the ups and downs of everyday life and help explain something about ourselves and the people we meet. It's not rocket science, in fact, it's not science at all. Whether you are an Aries or a Pisces, it is ultimately about people and what makes us what we are.
Influence of the signs
Aries 21 March - 20 April
Inclined to action rather than thought, they can come across as pushy and childlike, though really those born under the fire sign are warm-hearted, so long as they are getting attention. Determined and competitive, they are compatible with Leos and Sagittarians.
Typical: Keira Knightley
Atypical: Marlon Brando
Taurus 21 April - 21 May
Straightforward and with a great hatred of change, Taureans will never make a snap decision, or react in haste. Known as the most loyal and reliable sign of the zodiac.
Compatible with Virgos and Capricorns.
Typical: Immanuel Kant
Atypical: Fred Astaire
Gemini 22 May - 21 June
Generous, affectionate and impulsive, Geminis cannot stand to be bored and are impatient. Youthful, enigmatic, but prone to changing their minds. Compatible with Librans and Aquarians.
Typical: Bob Dylan
Atypical: Henry Kissinger
Cancer 22 June - 23 July
Softies under the shell, people born under the water sign have good memories, with a love of history and collecting things. Sometimes secretive, but with a great sense of humour; creative cooks. Compatible with Pisces and Scorpio.
Typical: Estée Lauder
Atypical: Mike Tyson
Leo 24 July - 23 August
Arrogant and flamboyant, Leos are loud and prone to showing off, But they are also very generous and can be very helpful. Rarely moody, they are often in the company of other people. Compatible with Arians and Sagittarians.
Typical Leo: Mick Jagger
Atypical Leo: Halle Berry
Virgo 24 August - 23 September
Often misinterpreted as being needlessly fussy, Virgos are perfectionists. Extremely inquisitive, they like to be on the move as opposed to relaxing, and are hard workers. Compatible with Taureans and Capricorns.
Atypical: Ingrid Bergman
Libra 24 September - 23 October
Emotionally impulsive, Librans love being in love, and get depressed if they feel unwanted. Affectionate and interested in people, these air signs are bad at making decisions. Compatible with Geminis and Aquarians.
Typical: Brigitte Bardot
Atypical: Margaret Thatcher
Scorpio 24 October - 22 November
Dark and mysterious, Scorpios are the most sexual sign of the zodiac. They are deep, emotional and can be extremely jealous. They will stay loyal to their friends for life, unless they are crossed. Compatible with Cancers and Pisceans.
Typical: Ethan Hawke
Atypical: Sylvia Plath
Sagittarius 23 November - 21 December
Generous and friendly, Sagittarians are so open that the world often knows what they are up to. Good sense of intuition and very honest, they can also be big spenders. Compatible with Arians and Leos.
Typical: Frank Sinatra
Atypical: Winston Churchill
Capricorn 22 December - 20 January
The luckiest star sign in the zodiac, Capricorns can be trusted to keep secrets. Creative, sensitive and patient, they tend to be very close to their families. Shy when they meet people. Compatible with Taureans and Virgos.
Typical: Kate Moss
Atypical: Elvis Presley
Aquarius 21 January - 19 February
Original, inventive and smart, Aquarians are incredibly friendly. But they are the know-alls of the zodiac and are late for everything. Compatible with Geminis and Librans.
Typical: Jennifer Aniston
Atypical: Yoko Ono
Pisces 20 February - 20 March
Pisceans are deep, with a good sense of intuition. Gifted in anything creative; from design to music. The first to start a rumour, and find it difficult to keep secrets. Find it difficult to say no. Compatible with Cancers and Scorpios.
Typical: Sharon Stone
Atypical: Michael Caine