Ok you got me. It is actually more than half the battle. That said, the precise number is in dispute, as various experts have rung in on the subject over the years.
Perhaps one of the most famous (and somewhat nototious), is Sun Tzu, who sowed some of the initial confusion on this subject when he said, "Knowing your enemy, you will win half the time. Know yourself, and you will win half of your battles. Know both and you will always be victorious." As you can see, the words "knowing", "half", "the" and "battle" are present, but seem to imply that you can win without doing.
Several centuries of debate followed, and the issue seemed to be in deadlock. It took GI Joe to clear things up, who famously added the crucial ingredient "is". He went a step further and actuallyt strung these words into a sentence, in a particular order, to achieve the full effect. Millions rejoiced at the thought that this was settled for good and all, only to find continued discord.
A reactionary group, sticking to the original Sun Tzu, insisted that 2500 years of debate were for nought, and repudiated GI Joe.
A third group arose, trying to reconcile the 2 camps, and in a mathematical attempt, simply applied an average. So the current version is: "Knowing is 3/4 of the battle." The Jury is still out on whether this will stick, but many are hopeful.
Now give me a fucking llama.