MY COLLEAGUE, THE woman writer, comes over to chat and she talks as if I'm not supposed to notice. She continues to talk and all the while I'm wondering if I'm supposed to say something, supposed to notice, supposed to look or maybe not look -- wondering all the time what the rules are. Finally, I ask. "Am I supposed to notice that you're not wearing a bra?"

She is wearing a sheer blouse. She stops talking and looks directly at me. No blush comes to her face. No stammer hits her tongue. Yes, she says. Yes, normally, I'm supposed to notice, but not this day. This day she is braless because the office is very hot and she took off her sweater and this was something she had not planned. Normally, she would never go braless in the office, she explains.

Okay, so this day, the rules having been explained to me, I do not notice. Usually, though, the rules are not explained and quite often I do not know where to put my eyes. I am not alone, of course. Lots of men have this trouble, one of them being a colleague who was seated at dinner next to a woman whose neckline plunged below table level. The next day, we are crossing the street, heading for lunch, and he is telling me about it.

"What am I supposed to do, Cohen?" he asks. "Do I look or don't I look?"

"You look," I say. "She wants you to look."

"But I don't want to look," he says.

"Then don't look."

"She wants me to. I'll hurt her feelings."

These are not easy times. The rules are constantly changing and no one knows any more what they are. It is like growing up all over again, having to learn new rules, feeling about women as tourists feels in a foreign country -- you know something of the language and something of the customs, but never enough to get the punch line of jokes. That's the way it is when you're a kid, when you're learning, say, that no does not always mean no except when it means no, or that it is no compliment to be liked as a person or to be told -- and lo the many times I heard this one -- that you have a wonderful personality. It it a far better thing to have shoulders.

Not much of this has to be relearned. Some of it is funny or trifling, as with the guy who complains that he never knows when he is supposed to pay for a woman's meal, but some of it is fundamental and, in a way, sad. You could see this confusion written on the face of John Rideout, the Oregon man accused of raping his wife. The truth of the charge aside (he was found not guilty), he did say that he thought a husband could rape his wife -- he was entitled. No one had told him the rules had been changed.

Somewhat the same thing is happening in corporate America, where male executives react with dismay when they think they've been gentlemen only to be told they've discriminated. Once, for instance, chivalry forbade the assignment of newspaper women to certain beats -- night police, for instance -- and more recently women were banned from working at certain tasks by the American Cyanamid Co. for reasons of health. It seems that the executives who made that decision did so believing they were doing the gentlemanly thing -- "on the side of the angels," one of them said. They did not take into account how women don't want to be treated any different than men. Clean up the workplace for both sexes, they say.

For us just plain folks, the confusion comes in daily life. I don't know any more whether I should allow women to enter and leave the elevator before me, and the fact of the matter is that most of the time I don't. I used to defer, thinking this was some sign of respect, although for the life of me I could not figure out why I should respect women just for being women. Later, I realized that this has nothing to do with respect, but with lack of respect -- seeing women as dainty and fragile and needing special consideration. Out of deference to the women's movement, I give up my seat on the bus only to elderly people of either sex and pregnant women. This is not a sexist act. I would give it up for pregnant men, but there aren't any.

I do not any more know how to respond to airline reservation clerks who answer the phone with their first names since I have learned not to call women by their first names but to treat them as people. When I hear, "Hi, this is Debbie," I feel like saying, "Hi, this is Dickie, I'm interested in a flightie..." and I can't even begin to tell you how uncomfortable a Playboy Bunny makes me feel. The only thing worse than that is a walk down a nude beach where I don't know if I'm supposed to look or not look. Just how you look at a nude woman as a person is beyond me. Persons are men.

What it comes down to, really, is encountering sex, or what is usually associated with it, in the strangest places and being caught between your natural inclinations, say to look, and your training or your upbringing or whatever it is that tells you not to look. Some women will say it's our problem, and indeed it is, but you cannot say that and then exonerate women who dress inappropriately, flaunt their right to be comfortable at the expense of the comfort of others. They, too, have a problem. Say what you want about them, they are not gentlemen.