''Every man,'' wrote Emerson, ''passes his life in the search after friendship.''
How we conduct the search - and what we find - depends in large measure on what we learn as children.
Possibilities for friendship are everywhere, but often we are unaware of them. We have a kind of tunnel vision in looking for friends - and we pass it on to our children.
We teach them, inadvertently, to seek friends only among their peers. We encourage them to look for duplicates of themselves in their friendships:
''John's your age and likes baseball and soccer. You two will be great friends.''
''Linda's in your grade, she likes music, too. She'll be a good friend for you.''
''The new family next door has a child in your class. You'll be great pals.''
We rarely suggest, or even acknowledge, the possibility of his having a friend who is not his peer.
Children who have access to an extended family sometimes experience a special friendship with an aunt, uncle, grandparent, or older cousin.
I was blessed with aunts and uncles who were not just my relatives - but my friends. They were people to laugh and wonder and speculate with - and to confide in. They were the source of enormous pleasure in my childhood.
Because of my aunts and uncles, I learned early that people older than I am have friendship potential. But many young people are not open to friendship with people older than they are - because they have experienced only peers as friends.
And yet, a friendship with someone older can be a source of pleasure and growth and comfort.
Recently, a young woman wrote to a widely syndicated columnist describing her loneliness and feelings of isolation because, ''My husband travels on business and there is no one my age in our neighborhood.''
The difference in age, she felt, precluded any possibility of friendship.
I remember when my oldest child was very young and the two of us were alone a great deal. Our neighbors, Jim and Ruth, 20 years older than I, became our friends - and have remained good friends.
A man who recruits college graduates for positions in a prestigious national firm told me not long ago that highly qualified young people sometimes turn down an outstanding opportunity because ''There's no one in that department my age.''
They settle instead for a position with less pay, less potential - and more peers.
I remember my first teaching job in a new town. Everyone on the faculty was considerably older than I. John, a teacher many years my senior, became my friend. He offered practical advice, a delightful sense of humor, and a gentle philosophy.
John retired two years ago but still drops by our house to bring home-grown tomatoes, a book for the children, or to share stories of his boyhood adventures in Missouri - which delight my sons. Now, he is their friend, too.
My children learn from these friendships. They don't have, as I did, aunts and uncles and cousins close by. But they know that I value the friendships of people of different ages and backgrounds, people whose personalities, professions, and politics may be different from my own.
Children are more apt to do what we do than what we tell them. If we have as friends only those whose lives duplicate our own, our children are likely to do the same.
If we, as married couples, socialize only with other married people, we set the example of limited friendship.
If we enjoy only the company of people our own age, we are teaching the first lessons in ageism. And we are, in effect, reducing our children's chances of friendship throughout their lives.
There are many advantages to having older friends. We can benefit from their experience, gain a sense of perspective from their insight. As role models, they can be invaluable. And competition and envy, two factors that sometimes erode friendship, are largely eliminated.