in /at

Hi, does anyone know the difference between: "in the beginning" and "at the beginning" ? (same thing for "in the end" and "at the end"). A pupil asked me to explain it but i couldn't come up with anything smart!

[Mister Micawber]

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As with most in/at dichotomies, at is a point (one-dimensional) reference and in is a 2- or 3-dimensional reference.

In the beginning and in the end carry a connotation of during-- that is, the beginning and the end have, in some sense, duration. In the beginning, God created God created the heavens and the earth: this tells us that it was not instantaneous, but that the Creation took some time. (Posters, please save your theological arguments for another thread).

At the beginning or end considers the start or finish as a simple endpoint on the line of development. '[This] is a world map summarizing the extent of geographical knowledge at the beginning of the seventeenth century.' Here the start is just a point relative to the broad expanse of the century.

Of course, there are many situations in which either will do and no one will be the wiser: In/At the beginning, I thought it was true love, but at/in the end, I realized it was only about sex.
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