Physics began with a question: what is everything made of? Is everything made of the same underlying stuff?
Physical things are different on a human scale (e.g. solid, liquid) but if bigger things are composed of parts, and parts of parts, then at the bottom of that process, is everything made from the same thing?
That was originally a question about matter and the ultimate constitution of physical things. But eventually, physics (particle physics, relativity) shaded into cosmology. The nature of time, the origin, evolution, and fate of the universe. Attempting to answer a question about what things are made of led to further questions about the ultimate nature of time and space, past and future.
On a related note, this is from The Feynman Lectures on Physics:
ReplyDelete"If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis (or the atomic fact, or whatever you wish to call it) that all things are made of atoms—little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied." (Source)