I was perusing the Wikipedia article on the whole split-infinitive mythos, and I just wanted to share something that two great writers, of fiction and linguistics respectively, had to say:

 Quote:
By the way, would you convey my compliments to the purist who reads your proofs and tell him or her that I write in a sort of broken-down patois which is something like the way a Swiss-waiter talks, and that when I split an infinitive, God damn it, I split it so it will remain split, and when I interrupt the velvety smoothness of my more or less literate syntax with a few sudden words of barroom vernacular, this is done with the eyes wide open and the mind relaxed and attentive. The method may not be perfect, but it is all I have. (Raymond Chandler to an editor at The Atlantic Monthly.)

and

 Quote:
To is no more an essential part of an infinitive than the definite article is an essential part of a nominative, and no one would think of calling the good man a split nominative. (Otto Jespersen. (1905) Growth and Structure of the English Language.)

Ceci n'est pas un seing.