We all know that the phrase Many hands make light work is an idiom. We know it is not talking about lights, in the sense of an electric light. We know it means making the task lighter and easier by spreading the load. Getting more people to join in to get the task done, spreads the load and makes the task easier for everyone.
Understanding that it is an idiom and not meant to be taken literally is an example of high level thinking.You might even say it is one of the hallmarks of being human. We understand that big ideas can lie behind simple statements that are not meant to be taken literally.
Many hands make light work is an old idiom. It dates at least to the 1300s, because we have the evidence that it appeared in print then.
The idiom is also an example of synecdoche, which is a way of describing something by referring to a part of that something. When we say many ‘hands’ make light work we are not referring only to the hands, but to the whole person.