What I liked best about the new tax proposal wasn't that it might enhance, reduce or freeze revenues, but that it was originally written on a computer. I thought it was hi-politech of Donald Regan to present a proposal saying, it "was written on a word processor. It can be changed."

I liked the thinking mode he had chosen. Instead of creating old-time typewritten legislation that would resist rewrites, and have to be cut and pasted until it looked like a collage, he was as open as a screen full of green letters. Ideas could be added, deleted, moved by the White House and Congress and not even the computer operator would know what had been there originally.

You can imagine my disappointment when Regan hardened up his software frame of mind. He found that people wanted to rub out his whole text. He started to worry and to suggest that the proposal was only open for modest corrections.

"What I meant when I said it was written on a word processor is that a word or a thought can be changed here and there," he said. "You don't rewrite on a word processor." This technological nonsense was uttered before a roomful of journalists at the National Press Club who promptly went back to their offices to write and rewrite the story on their word processors.

Despite Regan's hasty recanting from his experiment in hi-poli-tech, I still think we're on to something. Forget about the tax proposal and imagine what the government would do if it could process and reprocess its every word. Think how far Big Brother could have gotten with one of these things.

In the days of our forebears, messages from the Leader were written in stone. This was a single but adequate technology for the task. Moses came down from the mountain with two tablets and Ten Commandments instead of a printout. God didn't need an electronic eraser. He certainly didn't have any second thoughts. He didn't suddenly decide that the second commandment should be the seventh and that the eighth should be fixed because He hadn't said it just right.

But less celestial leaders need a bit more editing. Mere mortals tend to be messier, far less stable than the Creator. There is nothing that worries a politician more than being accused of inconsistency. One politician's growing and changing is another voter's vacillation. What a relief it would be for them if life were an open file that was continually available for editing.

A campaign promise made in an excessive moment? Delete it. A vote that didn't sit well with the constituency? Rub it out. A rash proposal? Insert a few well-chosen qualifiers.

The possibilities for rewriting tax proposals are nothing compared with the possibilities for rewriting history. If we move to a softer world and eliminate the last hard copy -- be it print or video or tape recorders -- then none of them would ever have to live with their mistakes. No ambassador need be reminded of his former confidence in the shah. No regulator need reread his approval of Three Mile Island. Instead of eating their words, they could have them devoured in megabytes.

The remarkable thing about a word processor is the way it hides the process of writing words. Writing on a computer is like writing in electronic sand. It is not the capacity to store memory but to erase memory that is really so impressive.

The historians, the archivists and assorted dusty people have already latched onto this problem. Personal letters have been replaced by telephone calls. Notes are no longer passed by hand, but sent electronically. People who once wrote on the backs of napkins write on disks, and first drafts disappear into the black hole of the computer. The personal papers of the famous are reduced to impersonal files.

But for government officials it bodes pure bliss. No more paper shredders. No more paper. Nothing permanently etched in memory. Nothing permanent. No memory.

That is why I believe that Secretary Regan will inevitably go back to his open-file support of word processing. He has more than any of us to gain. Think how much easier his life would be if he could delete from our national memory 13 unlucky bytes uttered by his presidential boss: "No tax increase."