At some point in the future, humans will think of us and our way of life as “backwards,” and they will be right. But some things will be particularly difficult to comprehend.

• Carnivorism: Parents will tell their children that humans used to eat other animal flesh, but it will be difficult to convince them. People will look back on us as we view cannibals and cavemen. Everyone will be grossed out.

• Invasive surgery (especially plastic surgery): Scalpels cutting through flesh and causing bloodshed? Seriously? And some people actually chose elective surgery for non-essential reasons! All cures and treatments will be non-invasive and the product of genetic engineering. Our age of medical miracles will be thought of as the Dark Ages.

• Internal gestation: Sex will go on apace, but birth control will be perfected, babies will be planned with precision and all new life will be “hatched” and nurtured in vitro in artificial wombs. Pictures of pregnant women will be needed to convince our future selves that babies were carried for nine months and childbirth actually occurred.

• Factory workers: There were people who actually use to manufacture things by hand and with primitive machinery before robotics did all the work. The future will look back on these people as having lived horrid existences, failing to understand the benefits such work brought, even beyond the material.

• Prisons: We took humans who behaved badly and warehoused them in conditions that made them worse before releasing them back into the general population. People of the future will look back on us in disgust. They will have a completely different system. It will likely be just as bad. People even further in the future will look back on them in disgust.