[new299]

"What was the reason for creating the patent system in the first place? To give people an incentive to invent new things: if someone invests the time in coming up with something novel, the legal system would give a temporary monopoly in return."

If someone invests the time in coming up with something novel, and discloses it publicly. If I remember correctly, public disclosure was the more important part of the original motivation for the patent system.

"patents are intended to facilitate and encourage disclosure of innovations into the public domain for the common good. If inventors did not have the legal protection of patents, in many cases, they might prefer or tend to keep their inventions secret."

That's from Wikipedia, but I'd be interested to see a better reference if anyone has one. So, to play devils advocate, given that motivation you can see an argument for software patents. Potentially a stronger one than for other patents.

It's much easier to obscure algorithms than other inventions. If an algorithm is not patentable, many companies might choose to just obscure the algorithm either by offering it as a service or obscuring the code.

By allowing software patents for a complex algorithm the method is released into the public domain in return for a limited monopoly. After the term of the monopoly, the algorithm will be freely available for use by everyone.

[tmzt]

This might be a better one, from the US Constitution:

  To promote the progress of science and useful arts, by
  securing for limited times to authors and inventors the
  exclusive right to their respective writings and discoveries;

http://www.law.cornell.edu/constitution/articlei#section8

[peterashford]

When do you think patents were first envisaged? Hint: it's a little bit earlier than the existence of the US

[hackinthebochs]

The basis for patents in US law is the only thing relevant to this conversation.