Right. And, in exactly the same sense, facts, experiments and observations are not science.
OTOH, conjectures, guesses and postulations consequentially connected to facts, experiments and observations, are science.
Both the speculating and the testing are necessary. It's not science without both.
What worldview you start with determines what conjectures, guesses and postulations you come up with.
Maybe so. Maybe not. But the most important point is that this is strictly irrelevant.
The process whereby, or the basis upon which, you construct a scientific hypothesis, literally does not matter. Sure, as a practical matter, some ways will tend to work well and others not so much, but the point is the validity of a hypothesis is completely independent of how or why you formulated it.
The only things that matter are if your hypothesis or theory is structured in a scientific fashion (avoids ad hoc explanation, is consistent with known facts, is testable by yet unknown facts, differs in crucial implications from alternative explanations, etc) and how it fares on testing against observation.
Science has to do with the observable present, not the unobservable past.
This distinction is likewise artificial and irrelevant. Again, the only thing that matters is that your theory or hypothesis is well constructed and has testable implications. Whether those implications relate ultimately to events presently occurring, or to events that occurred long ago, doesn't matter, at least as to whether or not your conjecture and it's testing constitute science.
First bear in mind that almost nothing is really ever "directly" observed. In the strictest, most literal truth, it's not just the past that is "unobservable," but also the present. For instance, I believe it is only in the last decade or two that scientists were able to actually image an atom. Does this mean that all prior atomic theory has to be thrown out as based on the unobservable? Of course not.
Or consider chemistry. Even if you can, very occasionally, with great difficulty, and under very special circumstances, in some sense "see" an atom, chemical reactions are a different matter. They occur FAR too quickly and are FAR too dynamic to ever directly image and observe. And yet, without ever having witnessed a single, solitary chemical reaction, but only by observing their putative (i.e. "guessed at") effects and consequences, we have been able to construct the entire science of chemistry over only a few hundred years.
But since chemistry is about chemical reactions, and chemical reactions are always unobserved, you would be telling us that chemistry is not science.
Secondly, just because some events natural science is interested in occurred in the past -- it's not as if they occurred in some different universe. Since they occurred in this universe, under the same natural laws that presently govern it, those events are liable to have consequences that are observable in the present. Or, rather, our theories about their causes are liable to have consequences as to facts that are presently observable.
So, in short, it's not the events themselves, about which you theorize, which have to be observable. They almost never are. It's the consequences of your theory which must be observable.
From one that does protein chemistry and antibody-antigen reactions all day...
Very well put.