There’s a distinction between contradicting everyone else (lonely dissent) and proposing something new. Dissent takes courage, not necessarily proposing something new, because one might suppose that people will find the new thing acceptable. For example, I’m not sure that Ettinger needed more courage than modern cryonicists—he gives the impression that he expected his idea to be accepted as an obviously great idea, once it was proposed. It seems he was rather surprised by the world’s reaction.
There’s a distinction between contradicting everyone else (lonely dissent) and proposing something new. Dissent takes courage, not necessarily proposing something new, because one might suppose that people will find the new thing acceptable. For example, I’m not sure that Ettinger needed more courage than modern cryonicists—he gives the impression that he expected his idea to be accepted as an obviously great idea, once it was proposed. It seems he was rather surprised by the world’s reaction.