What are the purpose of antitrust laws, and what is the rationale behind the Patent and Copyright Clause? 

Antitrust laws are designed to protect consumers, and promote competition by prohibiting companies from engaging anticompetitive activities such as price-fixing, collusion or mergers which would lead to monopolies. The laws were designed to encourage fair competition, and stop businesses from gaining an unfair edge over competitors.

The Patent and Copyright Clause is a section of the US Constitution that grants Congress the power 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”. The clause is used to justify copyright laws that protect intellectual property by giving the creators of works control over their use or reproduction. This clause also provides an incentive for innovators by allowing them to benefit from their innovations without having to worry about being copied.