There is a crucial assumption in science without which science will be completely useless, and that is “Laws that govern the universe are the same everywhere, past and present”. This assumption allows us to accumulate knowledge acquired by science. If the assumption holds, we can apply knowledge of the properties of electrons discovered in a lab to make computers that can run in your bedroom.

There is also a crucial assumption in history, “history repeats itself”. Without it studying history would just be a frivolous pass time. Of course, this assumption isn’t as strict as the scientific one. History doesn’t literally repeats itself, instead, at a macro level, there are patterns in history that come up periodically. This assumption allows you to use knowledge of history together with the present to make decisions that effect the future. If trickle down economics didn’t work in the great depression, and if there are many parallels to between the great depression and the current economic crisis, then there’s a slim chance that trickle down economics will work now.

Those are two big assumptions that make entire academic diciplines work, but what about assumptions that make smaller things work? Standards and specifications like RFC and ISO allow engineers to make crucial assumptions. I know that my CD from Sony will work in my CD drive from Pioneer because there is a standard specification that defines how a CD drive should be made and how a CD should be made to work with it. This allows Sony to make a CD that works with Pioneers CD drive without actually talking to Pioneer directly.

More closer to home, when you visit a restuarant, you can make the assumption that you will be fed. The resturant can make the assumption that you will pay after you eat. This assumption provides both you and the restuarant an incentive to interact.

Crucial assumptions make the world work.