Apart from "the usual suspects" that have already been cited in the comments, I would suggest some study of the topic of quantum mechanics, plus what some of the "big names" have opined on the nature of the study of physics. Quantum mechanics is one of the more challenging concepts in physics. It thus shows scientists stretching their ability to the max.
Please be aware that all the books I link to here have multiple editions. I just linked the first edition I found on Amazon. You may well be able to find a similar edition in your university library, or at some other book seller for less. Trying to be sensitive to the budget of a freshman.
In the book QED: The Strange Theory of Light and Matter, Feynman offers the opinion that it is "crazy." And he also brings forward an approach that has been dubbed "shut up and calculate." Meaning, the theory is a formalism that makes predictions that can be tested. Just go ahead and use the formalism but don't worry too much about what it means. Many a physics student has applied this attitude and gone through not just a university degree but entire academic careers as professors, even Nobel winners. By far not the least being Feynman himself. But it is often held as unsatisfying even if it does work.
"Speakable and Unspeakable in Quantum Mechanics" by J.S. Bell provides discussion of the concepts around what can be observed, what can be claimed, and what cannot, within the frame of QM. Bell is the originator of the theorem named after him, which provides a very sharp observational sword to decide if the world is or is not quantum mechanical. To date, it is still the case that QM is undefeated. A chapter is devoted to this theorem. Bring some mathematical ability because he does not pull any punches.
Bohr wrote on the philosophy of physics. This is volume 1 of 3. Again, bring some mathematical ability. Others among the "big names" in physics have written on the topic of philosophy and physics: Heisenberg, Planck, and Pauli just three.
In "The Evolution of Physics", Einstein and Infeld write about the process of new ideas becoming accepted in physics. I found this book quite interesting for a number of aspects. It talked about the physics and I learned some interesting concepts. It talked about the philosophy of science, also interesting. And, briefly, it talks about the characteristics of the human mind that are required to make progress in physics. Which, when I read this in 1st year undergrad, was intensely interesting.
I may be misremembering the quote but I seem to recall that this book contains a line something like "physics is mostly character." By which is meant that being honest and having self critical integrity to admit when something is wrong is a vital part of doing science. I have sometimes given this the colorful explanation that a scientist's waste paper basket is his most valuable tool. Figure out where the mistakes are and stop making them.
Which, of course, brings us back to Popper and the idea of falsifiability.
