The issue about alchemy vs science should also be of one's attitude towards approaching either subject.
If one approaches alchemy with the intent of becoming rich by buying lead in bulk and then somehow transmute them into gold, they are wasting their time. If alchemists could do this, they would have done it by now. It would be mundane process by now, or would so if it somehow appeared.
However, if one approaches alchemy out of curiosity, and/or because they find the spirituality interesting and engaging, then that's their choice to follow and investigate this spirituality. That is their choice, arguably their human right, to believe these things and live their life with these beliefs. As long as they are not harming others, not making claims that can be proven to be false or forcing others to their beliefs, then they have the right to do this.
If one wants to do alchemy to learn how our ancestors thought and believed the world around them, that is a historical interest and may have historical value. If one does it to be a member of an "alchemy club", that has as much value as any arbitrarily-made social club.
As for science...
But you see, even the laws of physics are not necessarily correct.
Because no scientific theory is meant to be 100%, absolutely correct. Scientific theories are meant to describe something's behavior to a limited extent. If you want to describe behavior outside the limits of the previous theory, you need either a different theory or one that includes the previous one.
For example, Newton-level physics describe how gravity works, but not
why gravity works (to explain why gravity works would require approach, one that tries to brake down the nature of matter). As long as we are interested in describing something in context how something's gravity effects things, Newton-level physics will work. However, if we go to phenomenon that either either too small (the behavior of atoms at a sub-atomic level) or too large (the behavior of light), we need to change or expand the theory to accommodate those behaviors.
Great theories explained things that were not understood at the time. Quantum theory explained
the photoelectric effect and made predictions that were tested and turned out to be true (many computer chips and components of those components are based on quantum theory). The same idea is true of Einstein's relativity, because it predicted that a clock's energy state influence it's speed. We know that prediction worked
because GPSs work.
No scientists in their right mind goes out trying to prove something absolutely, irrevocably right or wrong. They set out what is
reasonably right, what can be falsified, what can be measured. What modern science does is trying to be
the least wrong it can be.
We do not know absolutely that the galaxies we see are real places. But we can detect light-emitting things within them, which Spectroscopy reveals to be be suns. We use spectroscopy in a wide manner to detect how matter and objects show photonic radiation, frequently with things here on Earth. All our observations reveal that all these glowing objects are stars that are like our sun. We have no reason to believe that these objects do not have mass, do not have a have gravity, that these objects are less real than the objects close to Earth, etc.
And that sort of brings an edge to a discussion in the idea of "science vs alchemy".
That alchemists discovered many chemical compounds and phenomenons does not excuse that their theory does not work, there does not seem to be a powder that can turn lead into gold by heating. Matter seems to be conserved in all chemical reactions (and only change in nuclear reactions), rather than to spontaneously come or go away in a transmutation. Earth, water and air appear to be composed of various elements that can be seperated or recombined at will. Fire does not appear to be an element, fire is merely a chemical process (plasma does not count).
In other words, if one wants to explore how the universe works as best one can do, modern science offers far more than alchemy. The products of modern science, made and predicted by modern scientific theories, are all around us: electronics, medicine, motorization, etc. The products of an industrialization comes hand-in-hand with modern scientific work. It is merely that to an outside observer to the processes that they appear unrelated, because closer examination shows that they are merely indirect. Like the GPS example before, the evidence and predictions of modern scientific theories are abundant. They are, because they were built that way even before their inception.
That is my view anyway.
I also HATE how one of the most famous alchemists ever, Nicholas Flamel, has been put off as "just another Harry Potter character".
Why? Alchemists already know the true(er) meaning of the person behind that name, they already know how he is a great alchemist because alchemists would study his works. Alchemists already value him.
To non-alchemists, his name is mostly meaningless anyway, just another historical footnote that is transcended into a fictional world. And the thing is, it's just that his name was dropped: the person himself didn't show up in the books, or if they did, they did not do so in a significant matter (at least, I can't remember him appearing in the book). So it's not like Rowling made a caricature out of him.