(I know that some of these have already been covered in posts on this board by other people, but I’m trying to get several of them together in a list.)
What if the ancient Greeks or Romans develop a place number system with a zero? The Greeks had to discover a number of their mathematical principles the hard way, by the painstaking use of geometry, because they didn’t have a decent number system. Surely it’s possible that some intelligent classical thinker with a fondness for unusual solutions could invent an entirely new number system.
What if the ancient Greeks or Romans developed crossbows? Many of the Hellenistic and Roman catapults worked on the same principle as crossbows, but there is no direct evidence that anyone ever designed a version that could be used by an individual soldier. (Some military historians think that crossbows may have been used by Roman soldiers in the 3rd, 4th, or 5th centuries, but there is no direct evidence for this.) Would this have had a major impact on the way that war was fought in the classical world?
Could an effective working steam engine have been developed in ancient times? We know that the basic principles were understood by at least a few Hellenistic Greek scholars. We also know that the Greeks actually built rails in some of their mines and had rail cars that were pulled or pushed by animals or people. What if someone had put the ideas of steam engine and rail car together? Is this even remotely plausible?
What if the bicycle had been invented earlier than the late 19th century? There is a controversial drawing in the notebook of one of Leonardo Da Vinci’s pupils that appears to depict a bicycle, although some scholars believe that it is a forgery done by one of the people who worked on restoring the manuscripts in the 1960s. What if Da Vinci or someone else around the same time built a working bicycle? Would it be too uncomfortable and/or dangerous to become widely used given the lack of inflatable tires and the awful condition of most roads at the time? Could a working chain be built with 16th century metalworking?
Native American civilizations never used the wheel for anything except children’s toys, largely because of a lack of domesticated animals to power wheeled vehicles. However, what if someone in Mesoamerica or the Andes or the Mississippi valley developed something like a wheelbarrow – a load-bearing wheeled vehicle that was powered by people rather than animals? It’s not surprising that this didn’t happen, given that wheeled vehicles in the “old world” were developed for animals to pull long before they were developed for people. Still, it could have happened – could it have made any significant difference?
What if gunpowder was developed earlier and/or was used extensively in weapons as soon as it was invented? The basic ingredients are common enough – I think that someone could have stumbled onto the idea in virtually any civilization in the world that had reached roughly the bronze-age level or higher.
What if gliders capable of carrying people aloft with at least some degree of safety had been developed before the 19th century? As an alternative, what if hot-air balloons had been developed earlier?
What if cotton, sugarcane, or rice had reached the Mediterranean world in Greek or Roman times and had become widely cultivated?
What if windmills and/or water wheels had become widely used in the Roman Empire? Windmills weren’t developed until medieval times, but it seems that the principle of a windmill was known, because there is an account of miniature “windmills” being used to power mechanical novelties in the Hellenistic period. Water wheels were developed during Roman times, but they apparently weren’t that widely used. It was only during the medieval period that they became common.
This isn’t really an “innovation”, but what if there was a species of cool-weather rice that was native to much of northern and western Europe? What if it was domesticated locally before wheat and other grains arrived from the Middle east, and remained the preferred crop in areas that were wet enough to grow it? If I remember correctly, rice produces more food per unit of land than most other grain crops, which is why rice-growing areas often have a VERY high population density. Could this give Europe a much higher population earlier in history?
What if the ancient Greeks or Romans develop a place number system with a zero? The Greeks had to discover a number of their mathematical principles the hard way, by the painstaking use of geometry, because they didn’t have a decent number system. Surely it’s possible that some intelligent classical thinker with a fondness for unusual solutions could invent an entirely new number system.
What if the ancient Greeks or Romans developed crossbows? Many of the Hellenistic and Roman catapults worked on the same principle as crossbows, but there is no direct evidence that anyone ever designed a version that could be used by an individual soldier. (Some military historians think that crossbows may have been used by Roman soldiers in the 3rd, 4th, or 5th centuries, but there is no direct evidence for this.) Would this have had a major impact on the way that war was fought in the classical world?
Could an effective working steam engine have been developed in ancient times? We know that the basic principles were understood by at least a few Hellenistic Greek scholars. We also know that the Greeks actually built rails in some of their mines and had rail cars that were pulled or pushed by animals or people. What if someone had put the ideas of steam engine and rail car together? Is this even remotely plausible?
What if the bicycle had been invented earlier than the late 19th century? There is a controversial drawing in the notebook of one of Leonardo Da Vinci’s pupils that appears to depict a bicycle, although some scholars believe that it is a forgery done by one of the people who worked on restoring the manuscripts in the 1960s. What if Da Vinci or someone else around the same time built a working bicycle? Would it be too uncomfortable and/or dangerous to become widely used given the lack of inflatable tires and the awful condition of most roads at the time? Could a working chain be built with 16th century metalworking?
Native American civilizations never used the wheel for anything except children’s toys, largely because of a lack of domesticated animals to power wheeled vehicles. However, what if someone in Mesoamerica or the Andes or the Mississippi valley developed something like a wheelbarrow – a load-bearing wheeled vehicle that was powered by people rather than animals? It’s not surprising that this didn’t happen, given that wheeled vehicles in the “old world” were developed for animals to pull long before they were developed for people. Still, it could have happened – could it have made any significant difference?
What if gunpowder was developed earlier and/or was used extensively in weapons as soon as it was invented? The basic ingredients are common enough – I think that someone could have stumbled onto the idea in virtually any civilization in the world that had reached roughly the bronze-age level or higher.
What if gliders capable of carrying people aloft with at least some degree of safety had been developed before the 19th century? As an alternative, what if hot-air balloons had been developed earlier?
What if cotton, sugarcane, or rice had reached the Mediterranean world in Greek or Roman times and had become widely cultivated?
What if windmills and/or water wheels had become widely used in the Roman Empire? Windmills weren’t developed until medieval times, but it seems that the principle of a windmill was known, because there is an account of miniature “windmills” being used to power mechanical novelties in the Hellenistic period. Water wheels were developed during Roman times, but they apparently weren’t that widely used. It was only during the medieval period that they became common.
This isn’t really an “innovation”, but what if there was a species of cool-weather rice that was native to much of northern and western Europe? What if it was domesticated locally before wheat and other grains arrived from the Middle east, and remained the preferred crop in areas that were wet enough to grow it? If I remember correctly, rice produces more food per unit of land than most other grain crops, which is why rice-growing areas often have a VERY high population density. Could this give Europe a much higher population earlier in history?