Be honest. If thinking "I could have done that" while walking around a contemporary art exhibition is the mark of a philistine, aren't you a philistine, too? I know I am. Much as we may know that it's not as easy as it looks to create a decent artwork, there are times when we come across something so simple, so unimpressive, and so devoid of technical merit that we just can't help believing we could have done as well or better ourselves.

What perhaps makes me unusual is not that I entertain such thoughts, but that I did go off and try doing it myself. My medium was the most accessible of them all: photography. I've been a dabbling photographer since I was a teenager. When I was 16, I saved up money from a summer job at a burger bar to buy the then entry-level SLR camera of choice: an East German-made Praktica MTL5. I bought filters, collected a four-part photography guide from a Sunday newspaper and used the black-and-white 35mm film for the inevitable attempts at arty prints.

However, I've never turned my casual interest into a serious hobby and my greatest achievement was winning a photography competition run by my local WHSmiths. If you ask me now about ISOs and f-stops, I'll only have the vaguest idea of what you're talking about. These days, I use either a Nikon compact or an Olympus PEN, that uses SLR-style detachable lenses on a compact-like body. With both, I'm using almost entirely automatic settings.

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There's no doubt that these incredible little machines can take great pictures. Some of the best serious photographers have used cheap cameras to take photos that stand up as works of art. But surely to pull this off you'd need to be very practised, with a deep understanding of how photography works?

Looking at many photographs in galleries over the years, I wasn't so sure. Immodest though it sounds, I did think that some photos I had taken were at least as good as the ones on the wall. I thought this again at last year's Open Exhibition at the Royal West of England Academy in Bristol. The very nature of the show invited me to try to prove my point. As with the Royal Academy's Summer Exhibition, anyone can submit a work for a small fee. It was irresistible. It didn't take hubris to believe I stood a chance. Three trends in art over the past century have opened the door for dilettantes to make their mark: technology, abstraction and conceptualism.

Before each of these developments, almost all of the arts required a combination of two kinds of ability, which for simplicity's sake we can call creative imagination and technical skill. Creative imagination is what enables a painter to conceive of what should fill the frame, a composer to hear things in his or her head before sitting down to transcribe them, or a sculptor to see what form a piece of rock could become. Such imagination does not generate a mental version of the exact result right from the start. But it provides the guiding vision for the creative process, one that is constantly shifting as new details reveal themselves in the mind's eye or ear.

To pursue this vision, however, used to require great technical skill. The world's best painting was no use in your mind if you didn't have the brush skills. A tune in your head would stay there if you couldn't write music. Even if you could plonk out the basic sequence of notes on a piano keyboard, you couldn't develop the melodies in your head into a complete work of music unless you could score the whole ensemble.

For some mediums, however, this is no longer a terminal problem. When we talk about the vision of the photographer, for example, we talk about his or her "eye": their capacity to notice something which, once captured, becomes a noteworthy aesthetic object. The technical aspect of photography is simply the means by which this vision is captured as it is desired to be. This requires control of lighting and focus above all else. But you can get a lot of this control in a simple point and shoot, so that anyone with a good eye can take very good photographs.

The main difference between dilettantes and the dedicated is that the former will often find themselves unable to exercise the degree of control necessary to achieve the desired result. They want to shoot a curious juxtaposition of stones on the cathedral ceiling, for example, but without a slow exposure and a tripod, the end result is going to be grainy and discoloured.

These limitations, however, simply result in a lower success rate, not inevitable failure. In good light with no focus challenges, it is enough to compose the frame and let the microchips in the camera do the hard work of making sure that everything is correctly exposed.

A similar change has come about with music. Now anyone with a computer on their desk can take a tune in their head and develop it as far as their patience will take them. It is now possible to score a whole orchestra while being unable to play any of its instruments.

It shouldn't surprise us that technology can take over the work of technique. They share the same Greek root – techne – and can both be routes to the same end product. Yet the replacement of one by the other strikes some as almost offensive, as though it is morally unacceptable that an untutored amateur could produce something to compete with the serious artist with his or her decades of training. But even setting aside technology, there are other reasons for believing that technical ability is not always and necessarily the key to artistic excellence. Many musicians and composers produce their best work while young. As they get older, they acquire more knowledge and experience of how music works, and yet they become less able to make it work for them. The difference between something so-so and really good is not always bridged by greater knowledge of how the medium works.

Nor does technical ability always require a specialised skill. Until the advent of creative writing courses, no major writer had to undertake wordsmith training to produce their masterworks. Practice is important, of course, but some disgustingly talented young souls produce better prose at first draft than experienced scribes manage only on their thirtieth.

Technology, however, is not the only reason why dabbling artists can sometimes compete with their more dedicated peers. In visual art, the rise of abstraction means that we now appreciate the aesthetic merit of what are, in formal terms, very simple arrangements of shape, colour and texture. Someone with a good eye can potentially come up with such an abstraction and need very little skill to execute it. The other key development has been that of conceptual art, where the idea is far more important than any craft. Andy Warhol only needed to have the inspiration: he could leave it to others, none of whom was more than merely competent, to execute them. Any one of us might come up with an equally strong idea that could be produced without the need for years of practice.

So, for many art forms, it is indeed true that "anyone could do that", in the sense that anyone has the technology or technique to hand to execute the idea. It has become possible for more and more people, often untrained, to express their creative imagination as doing so has become less and less dependent on technical expertise. However, not everyone can have the ideas, the eye or the ear to come up with something worth making real. That core of invention remains elusive, beyond most of us most of the time. The best answer to the moan "I could have done that" remains "but you didn't". No one else came up with the geometric lines and block colours of Mondrian before he did, not because they lacked the skill, but because they lacked the vision. Technology and trends in art have not, therefore, made really good art more democratic, they have simply widened the membership of the elite.

Given all of this, it should not be so improbable for someone such as myself to have work accepted by a major regional art gallery. So I submitted three of my photographs to the Royal West of England Academy's 161st Open Exhibition, competing with around 2,000 others. All of mine made the first cut.

That meant getting them framed and printed for the final judging. It also meant setting a price for the works, since everything in the exhibition is for sale. I decided on a limited edition of 25 for each one, charging £250 for an unframed print. That's not because I thought they were worth it but because I suspect, with art, pricing influences people's judgement of merit. It's as though people can't help thinking that a work selling for £50 can't be that good, while if it's going for £10,000, there must be something in it. So although I didn't see submitting my work as an attempt at faking it or pulling the wool over people's eyes, the pricing was an exercise in bluff.

Come results day, I was chuffed to find that the photo I thought my best had been selected. But there was a sting in the tail. There are always a handful of the 500 to 600 works selected that are not actually hung. Mine was among them. So although I can say my work was accepted by the Royal West of England Academy, you cannot see it there and nor is it listed in the catalogue. That has at least given me a name for what was originally submitted as "untitled". From now on, the work shall be known by the designation it was given by the academy: "Selected, not hung".

The Royal West of England Academy's 161st Open Exhibition runs until 26 January at Bristol, rwa.org.uk.

Julian Baggini's latest book is 'The Virtues of the Table' (Granta, £14.99)