We knew there was a recession the minute the Neiman-Marcus catalogue for Christmas arrived. Mickey Mouse on the cover, need we say more? Those cautious economists who require two corroborating signals for their recessions will please turn to page 21. The ''His and Her Gifts'' are the ultimate in a Neiman-Marcus Christmas. This year they are robots. Domestic robots! Utilitarian little machines that will vacuum your rugs, squeegee your windows, sound a smoke alarm, or extinguish the fire just in case the smoke doesn't turn out to be an overdone steak.
The sheer practicality is a giveaway. In golden olden days his-her gifts had a princely extravagance - a gaudy superfluousness - to them. They existed in a fantasy world where rugs never needed vacuuming nor windows washing. Remember the year of the his-and-her blimps?
There's even a budget ($15,000) version of these robots, with black-and-white television attached instead of color. So much for Hard Times!
Once a recession has been decided upon - whether your criterion is a Neiman-Marcus Christmas or two quarters of declining GNP - the economist has the delicate assignment of delivering the signal. Secretary of Commerce Malcolm Baldrige has proven to be a member in good standing of the break-it-gently school. ''A temporary glitch'' and ''a pattern of sluggishness'' are two of the euphemisms by means of which Mr. Baldrige brought the news to his countrymen.
Other economists spoke bravely of ''a downward trend'' and ''a technical adjustment.''
Even Walter Heller, an economist associated with Democrat administrations, chose his words as if the messenger would be blamed for the message. The economy , he suggested, is now in ''the doldrums,'' undergoing ''a slowdown,'' or experiencing ''the sniffles'' - pick your metaphor.
Once the awful word ''recession'' has been uttered - and it must never, never be spoken without a soothing adjective such as ''slight'' or ''mild'' - then the question naturally comes up: What does one do about this almost negligible occurrence, hardly worth mentioning?
Here the burden shifts from economists to politicians. After the incumbents delivered the obligatory ''this-is-a-mess-we-inherited'' speech, they quickly segued into the other speech required of every recession-announcer: ''You can't make an omelet without breaking eggs.'' Or as one administration spokesman put it: ''A slight recession is perhaps almost necessary.''
Smooth though this crossover may be, we have a lot of trouble with the point where a ''mild'' recession becomes a ''beneficent'' recession - the first step to boom times for all. We keep wanting the recession-optimists to explain their argument, face to face, to the people out of work.
It is only one more step from such exercises in recession-appreciation to the assertion that the recession has been induced deliberately as part of a master strategy. But we anticipate. Nobody in the Reagan administration has gone so far yet. This stern logic is left over from President Carter, whose economic advisers recommended that he start a small recession in order to fight inflation. How the man tried to ''cool down the economy,'' as the euphemism went in those days!
''Next quarter for sure,'' the White House kept saying. ''A recession in the next quarter - we promise.
Mr. Carter never pulled it off, and he was forced to leave office with the sneers of economists in his ears (''If he can't do a recession, what can he do?'').
We did not hold the failure against him, and we still find it somehow oversubtle - this determination to see the positive side of a recession. In our lexicon the positive side of a recession is called prosperity.
On the cover of the Neiman-Marcus catalogue Mickey Mouse is perched - a little tensely, we thought - on the driver's seat of a sleigh. But hark, at the back, horn to joyful lips, an expansive Pluto blasts forth a motif of unreserved good cheer.
What does Pluto see that Mickey and the other economists fail to see? Who knows? But it isn't a recession, ''mild'' or otherwise, we can tell you that. We're ready to follow the jolly mutt into fiscal 1982 just to find out.