"Governor Thomas was so pleased with the construction of this stove...that he offered to give me a patent for the sole vending of them for a term of years; but I declined it from a principle which has ever weighed with me on such occasions, viz.: That, as we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously."
--Benjamin Franklin, Autobiography.

Our copyright and patent laws exist because not everyone can be expected to afford to be as open-handed as Franklin, and accept a share in the overall improvement of society as the sole payment for the invention or writing. But the principle remains valid: "as we enjoy great advantages from the inventions [I would add, and the writings] of others, so we should be glad of an opportunity to serve others by any invention of ours." This principle is implemented by the expiration of copyright and patent after a reasonable time. Copyright and patent holders who petulently view expiration of their monopolies as a "taking" are misconstruing the purpose and nature of these monopolies and grumbling about what is simply the requirement that they pay their constitutional dues, just as they have been paid for their improvement by the grant of a limited monopoly.

T.