Absolutely, but we only understand things in the context of what we already know, and we build up our understanding of new things from that. Besides, a theory

Absolutely, but we only understand things in the context of what we already know, and we build up our understanding of new things from that. Besides, a theory can also guide your experiments. For example, in physics, you wouldn't try to calculate the mass of all strawberry icecream in the world because physics doesn't, as a matter of course, consider the properties of strawberry icecream as particularly special or interesting. They're not a concept of physics, that is.