Plain version: a contract is a promise the parties make to each other, and a tort is a wrong the law forbids even when there is no agreement at all. If a roofer you hired never shows up, he broke his promise to you (breach of contract). If he drops shingles on a stranger walking by, he broke a duty the law places on everyone (a tort).
Contract law vs. tort law:
Contract: the duty comes from the parties' own agreement, and it runs between the parties to that agreement.
Tort: a civil wrong that injures someone apart from any agreement; the duty of care is imposed by law.
Every valid contract, including an insurance policy, needs four elements:
- Competent parties
- Legal purpose
- Offer and acceptance
- Consideration
California Civil Code §1550 states the same idea in its own words: parties capable of contracting, their consent, a lawful object, and sufficient cause or consideration. Notarization is not an element.
Offer and acceptance in insurance: the applicant who submits a signed application is making an offer. An acceptance must match the offer. If the insurer changes an important term, such as offering a higher deductible, that is a counteroffer: it rejects the original offer, and no contract exists until the applicant agrees to the new terms.