man, under the refining influence of culture, has become more sensitive to publicity, so that solitude and privacy have become more essential to the individual; but modern enterprise and invention have, through invasions upon his privacy, subjected him to mental pain and distress, far greater than could be inflicted by mere bodily injury. They then clarify their goals: "It is our purpose to consider whether the existing law affords a principle which can properly be invoked to protect the privacy of the individual; and, if it does, what the nature and extent of such protection is". Warren and Brandeis write that privacy rights should protect both businesses and private individuals. They describe rights in trade secrets and unpublished literary materials, regardless whether those rights are invaded intentionally or unintentionally, and without regard to any value they may have. For private individuals, they try to define how to protect "thoughts, sentiments, and emotions, expressed through the medium of writing or of the arts". They describe such things as personal diaries and letters needing protection, and how that should be done: "Thus, the courts, in searching for some principle upon which the publication of private letters could be enjoined, naturally came upon the ideas of a breach of confidence, and of an implied contract". They also define this as a breach of trust, where a person has trusted that another will not publish their personal writings, photographs, or artwork, without their permission, including any "facts relating to his private life, which he has seen fit to keep private". And recognizing that technological advances will become more relevant, they write: "Now that modern devices afford abundant opportunities for the perpetration of such wrongs without any participation by the injured party, the protection granted by the law must be placed upon a broader foundation". Modern tort law In the United States,"invasion of privacy" is a commonly used cause of action in legal pleadings. Modern tort law, as first categorized by William Prosser, includes four categories of invasion of privacy: Intrusion of solitude: physical or electronic intrusion into one's private quarters Public disclosure of private facts: the dissemination of truthful private information which a reasonable person would find objectionable False light: the publication of facts which place a person in a false light, even though the facts themselves may not be defamatory Appropriation: the unauthorized use of a person's name or likeness to obtain some