Living an ethical life is impossible. But that doesn't mean we shouldn't try.

Today my mobile phone woke me up. I set it charging - electrical consumption - while I had a shower under a mix of cheap chemicals, and got dressed into clothes which, while not Primark or high brand, were not hand woven hemp either.

Yes, being ethically irresponsible is part of life - it's a sad truth that if you were to cut out all unethical consumption, life would be impossible. And that's before you take in the financial implications - shelling out for fair trade everything is quite pricy. I've been having one of those Locke days - "what the hell am I supposed to do?!" - because it doesn't matter how hard I try, I still feel dirty.

And even when I feel I am being good - what's the point? I don't know anyone else who is consciously cutting down on their internet/computer usage; I'm the only person in the kitchen to pay £1.50 extra for chemical-free washing up liquid, I refuse to learn to drive so I will never get a car - but what's the point in my denying all these little, irritating things to myself when I know there are millions out there who leave all their computers on overnight and own private jets? In other words, my sacrifices are instantly cancelled out by other's excesses, making the whole thing pointless. I could switch off my computer now and save electricity - but out my window are a thousand businesses who've left their whole skyscrapers lit up overnight.

I've been applying my personal motto to it, it's the only way I can focus my efforts. You didn't know I had a motto? But it's Latin and all - "decus intelligentia" - and it came to me halfway through Rob Roy. It means "Duty with Intelligence", or, "do what you must - as far as it is sensible". In the context of Rob Roy it means "once someone has stolen your cattle, burnt your house, raped your wife and shot your dog, you are no longer required to challenge him to honourable single combat. You go down, sink to his level and kick his teeth in." In a Doctor Who sense, it's Warriors of the Deep episode 4 "cling to your pacifistic beliefs as long as you can, but there's a point at which mercy no longer extends to genocidal Silurians, and it's this point at which you can gas them in good conscience. Also, Doctor, this point actually occurred 45 minutes earlier..."

And so on - any film which ends with the entire cast being killed for no good "honour and peace" related reason which doesn't actually produce any practical effect. You're just dead - as Guildenstern puts it, "dying is not romantic, and death is not a game which will soon be over...Death is not anything... death is not... It's the absence of presence, nothing more ... the endless time of never coming back ... a gap you can't see, and when the wind blows through it, it makes no sound...". Last Samuri is another - they die for their beliefs, and they do it nobly, but the net effect is they end up dead - which is what the villainous Americans wanted in the first place.

As you can see, this motto is a direct reaction against trash heroic movies, but it applies to real life too. Defend your religion - but don't start wars about it. Go and help people in trouble - unless the odds are overwhelmingly against you. Protest your cause - but don't cry if it doesn't help. Recognise the point at which your actions no longer make sense, and give it up, but until that point fight like hell.

So, to ethical shopping. You know all big companies screw someone, somewhere down the line; you simply have to assume good faith, until explicitly told otherwise. There are always alternatives. I boycott Nestle - no Nesquiks, but you can replace it with equivalent cereals like Coco Rocks. I strongly boycott Proctor and Gamble because they still do animal testing, and this hurts folks, because I have to cut out Head and Shoulders, Tampax and Pringles. There are other shampoos, though, and as much as I hate to say it, there are also other brands of crisps. And at the same time, I ask myself what the point is, because not even my animal-loving ex-vegetarian friends can be persuaded to give Pringles up. People will never live ethically when it directly conflicts with their own self interest.

Before you ask, they test their chemical products on animals, not the crisps, but buying the crisps is still supporting them instead of forcing them out of business and to rethink their methods.

This requires some willful ignorance - I haven't looked too hard at the methods of the companies I still support, mostly because I know that to be big and successful you have to be dirty somewhere. But if ever I discovered there was something untoward, then I would ditch them too. Few things make me angrier than bitches who still shop at Primark - Primark bags make me want to push people in front of trains. Because it's not even a case of "I won't ask questions" - they know, they all know. If you sat them down and asked them to shoot a puppy as part of their Primark subscription, they wouldn't do it; but they can do it because out of sight is out of mind.

There is a point where being ethical is just hard to live. But there are other clothes shops. How many of them are any better? Probably not by much. But knowing and doing it anyway is wrong on a basic level. It also reminds me of an argument I had with my mum about the Christmas at Olympia fair.

Mum - "I really want to go to that next year".
Me - "you'd like it, but we can't because the company which organises it also organises Britain's largest arms fair in Central London, and invites countries with appalling rights records to purchase "defensive" torture equipment"

I can't remember her precise response, but I know that that didn't convince her. I find myself asking, what isn't convincing about "going to this event genuinely allows this company to involve themselves in murder and destruction, and make profit off the suffering of others". Yet Clarion won't stop organising arms fairs, all that will happen is my mum will be denied the fun of an admittedly great event.

Nothing will change. Yet if we don't, who will? It's like I always say about protests - 99% of which are a waste of time. The point of a protest is to stand up and show your feelings, to say you were there because you know it's right to be so - not because you genuinely expect the villains to buckle under pressure. It won't make any difference in a global sense; I just don't want to have any part in the destruction of the enviroment or opression on those less fortunate.

And that's it. Ethical living cannot be done. Even when it can be, the number of people too ignorant and/or lazy will far outweigh any contribution you can make to the side of good. Nor is it worth you living in a cardboard box with clothes made out of banana skins. It's like reality. You can't escape from it - it's everywhere, and part of who you are. The world is built on it. But you can make yourself as small a part of it as possible, and that's what I'm asking this week.

Don't get to the point where it's stupid. Just do what you can. Buy the greenest, fairest, cleanest products available. Not because it makes the world a better place, not because it has any impact at all. But because it makes you a better person.