Philosopher Simon Blackburn is a participant in next week's philosophy conference on truth and realism at St Andrews University (June 17-20)

Here he tackles the ultimate reality problems... from the pages of The Sun .

HE TOOK ME OVER HIS VINTAGE BONNET

Dear Derrida: I had the best sex ever with my lover on his car bonnet - knowing my husband was walking the dog yards away. I am 36, my husband is 38 and we've been married for 12 years. We have two great kids but our marriage is boring and our sex life is nil. My husband just works and goes out with his mates. One night my friend and I went to a '60s night for a laugh and met two guys. We got chatting. One of them was really funny and he made our night. He's in his 40s but looks younger and I took his phone number. We went for a drink the next week in his lovely vintage sports car and I told him I was married. We didn't make love that night but we did the next time we met after parking in a lovers' lane. One night as he dropped me off near our house, he lifted me on to the bonnet of his car and made love to me. I had an orgasm within seconds, then another. I knew there was a risk of my husband walking down the road with the dog but that added to the thrill. Then out of the blue my lover stopped seeing me. I know he's been hurt in the past and he didn't want me to leave my husband. He said our fling was just a bit of harmless fun, but I miss the sex and the great times we had together. I could go to the pub and find him but maybe I should just get on with my marriage. What do you think?

DERRIDA says : Thank you for sharing that with us. First, congratulations on avoiding nasty burns. Vintage car bonnets can be seriously hot. The immaculate paintwork is also easily damaged by bodily effusions, and this might explain your lover's withdrawal, in which case it will be hopeless to try to reignite the flame.

We must also consider the dog, which will have sensed something wrong when it eventually passed by the scene of your multiple epiphany, and may feel distressed about being unable to communicate it to your husband.

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The net result is: you need curing of exhibitionism and possibly masochism, your lover needs to stop being an anorak, your husband needs an IQ transplant, and your dog needs speech therapy. The chances of success are about equal in each case.

DEIDRE says : Your lover provided a very exciting and sexy break from your boring marriage, but you knew in your heart it wouldn't last.

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Now it's over, use the experience to resolve your problems rather than just settling for things going back to how they were.

Many long-term relationships become mundane, but it takes two to tango and you can make an effort to change things.

Start by treating your husband as you did your lover - you might be surprised at the results.

Your husband can't be any happier than you are with having a sexless marriage and it's time to look at why there's no intimacy between you.

If nothing you try works, tell him there is a crisis in your marriage and suggest you go for counselling at Relate (01788 573 241 or to try to put things right.

HER SEX DRIVE IS TOO LOW

Dear Derrida : I love my girlfriend but her sex drive doesn't equal mine. I'm 19 and she's 18. Since we first had sex I've craved it more and more. But she keeps turning me down and I worry I'm not good enough in bed. She says I'm the best she's had - but there is only her ex for comparison. Should I find someone with the same sex drive or stay with her and accept I won't get enough sex?

DERRIDA says : Isn't nature cruel? Follow the advice of the Cynics, who thought this kind of thing was best dealt with by a pre-emptive strike. Go and see There's Something about Mary to get the idea. Remember your graph goes down and hers goes up, so in about 15 years' time you may well be about equal, whereas a higher-octane partner might be thinking about leaving you for someone younger.

DEIDRE says : Putting her under pressure to have sex could be turning her off.

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Listen to how she feels about lovemaking and show her you're interested in how you can give her what she wants.

My advice line will help you strike a better balance.

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DAUGHTER OR NANNY?  

Dear Derrida  My teenage daughter is about to be made homeless, but my partner won't let her live with us. I've told my girlfriend blood is thicker than water, but I'm in a dilemma over what to do. My daughter is 18 and her mother and I split up when she was four. She's lost her job and is about to lose her rented home, which is being sold. She's been on the phone in tears and is at an all-time low. She tried harming herself a couple of years ago and that's on my mind non-stop. She left home at 16 and declared herself homeless - to this day I've no idea why. Before that, she bounced between me and her mother. My girlfriend was originally her nanny and, admittedly, my daughter treated her badly over the years. But I resent her telling me who can live in my house.

DERRIDA says : Hamartia is the fatal flaw that, according to Aristotle, generates tragedy, arousing pity and terror in spectators. Your fatal flaw was to give your daughter some ghastly parody of an upbringing, to which she has apparently responded by becoming attention-seeking and manipulative. No wonder the "nanny" is terrified. You can run from the furies, the guilt and shame that now pursue you, but your tragedy is that there is nowhere to hide.

DEIDRE says : What your daughter needs from her dad is the same thing she's needed throughout her childhood - to feel she's loved unconditionally.

Bouncing between her mum and dad doesn't seem to have given her security or happiness.

Neither did having a nanny who, in her eyes, probably took her dad away.

She may be 18 but is emotionally much younger.

Follow your instinct and reach out to her now. I hope your girlfriend will realise you may never have this chance again. Parentline Plus (0808 800 2222 or ) can give you both advice.

I LOVE MY SON

Dear Derrida : I haven't seen my son since he was two and I fear dying without meeting him again. I'm 29. When my girlfriend left eight years ago my solicitor said I had no rights to our child as we were not married. She married someone else and stopped me seeing my son. My dad died when I was four, so I now have to manage with neither him nor my only child. But my love for my son has never died.

DERRIDA says : M'learned friend tells me that unless you are a violent maniac, which of course may well be the case, you probably have rights of contact (and your son may have rights of contact with you) under the European Convention of Human Rights, which is now part of domestic law. So don't give up. Before suing your solicitor, however, read the first 100 pages of Bleak House . And cheer up: you shouldn't be talking about 'before I die' at age 29.

DEIDRE says : You need to separate the loss of your dad from that of your son.

For bereavement counselling, speak to Cruse (0870 167 1677 or ).

And for guidance on how to try to regain access, contact Families Need Fathers (020 7613 5060 or ). 

Unmarried dads can apply to the courts for contact.

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