This is what I meant by "getting into the epistemological weeds" heh. I'll requote your definition with emphasis.
> the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.
All three of the italicized aspects are not how the mind is studied. The mind is not a physical object. It cannot be observed or experimented with in a systematic way.
You can obtain three samples of three different kinds of steel and perform a destructive test on all three of them, then when you're done you can obtain more. This is materials science and you can get paid a lot of money to do it.
There is "neuroscience" where you do the same thing, with neurons. Neurons are not minds. You'll never learn how a mind works by studying neurons, any more than you can learn how a building works by studying steel. If you're looking to learn how a building works, steel is just one of the hundreds of topics you need to understand.
There is no "building science" and there is no "mind science", because buildings and minds are not physical, natural things. They're unnatural things, conjured up by human invention and imagination. Physically speaking, i.e. according to the best observation techniques the field of neuroscience can come up with, a newborn, a brain trauma victim, and a college student are all identical as your parent notes.
This deficiency in understanding is what the commenter you were responding to was pointing to. People thinking they can understand the mind by doing fMRIs. And thinking any kind of rigorous exploration and study as "science" leads to this kind of mistake.
Another example, computer science isn't science. It's math. Computers are deterministic, there's no point in running experiments. Computers are not natural, nor are they physical. Silicon is, and you can study that by running experiments and observing the results.
To get epistemic, knowledge comprises justified true beliefs. Science is a type of justification. There are other kinds. If you use other forms of justification, then you don't get scientific knowledge out of it, overloading science makes people believe that all knowledge that comes out of academia is scientific, i.e. made through repeated experimentation and observation, such that we can rely on it to not fail on us.