What are the effects of patents on innovation? In the classic theoretical framework, first formulated by Arrow (1962), patents protect against free-riding and create incentives for the provision of what would otherwise be a public good. This is in stark contrast with empirical evidence, according to which inventors find secrecy more effective than patents in excluding others from inventions. This presents a paradox: patents are theorized to be indispensable for innovation, but not all inventors find them useful in protecting their inventions. One way to resolve this paradox is to strictly separate inventions that can be protected with secrecy (because they are costly to reverse-engineer) from those that cannot (because they can be easily reverse-engineered). Most existing literature focuses only on the latter and assumes that inventors patent their inventions to make them excludable (the excludability motive). This paper shows that such separation may be miss-guided. Based on a survival-analysis of analysis of 4,741,023 U.S. patents, it shows evidence of inventors patenting not for the excludability motive, but to sell or license their inventions (the alienability motive). If this is the case, it would indicate a strong role of patents in disclosing inventions that would have been kept as secrets. This has significant implications on optimal innovation and patenting policy.