When we are tackling complex problems, we cannot guess or know what the right solution is. Complex problems, by definition, have no precedents. In social innovation labs, prototyping is used across the entire journey of the lifecycle of the lab. We must create and test alternative solutions and learn along the way – that is, to prototype them. This allows us to observe and anticipate, rather than guess at behaviour. We can more reliably identify and test our assumptions about the problem we are solving for. It also helps to dispel uncertainty about how something (a product, service or process) will work when applied to real life situations. In this way, prototyping allows us to dispel any fear or uncertainty about something not working, because we have tested it out already.