Imagine a very large room that has every surface covered by on-off switches.
We cannot see inside of this room. We cannot see the switches. We cannot fit inside of this room, but a toddler fits through the tiny opening leading into the room. The toddler cannot reach the switches, so we equip the toddler with a pole that can flip the switches. We train the toddler, as much as possible, to flip a switch using the pole.
Then, we send the toddler into the room and ask the toddler to flip the switch or switches we desire to be flipped, and then do tests on the wires coming out of the room to see if the switches were flipped correctly. We also devise some tests for other wires to see if that naughty toddler flipped other switches on or off.
We cannot see inside the room. We cannot monitor the toddler. We can't know what _exactly_ the toddler did inside the room.
That room is the human body. The toddler with a pole is a medication.
We can't see or know enough to determine what was activated or deactivated. We can invent tests to narrow the scope of what was done, but the tests can never be 100% accurate because we can't test for every effect possible.
We introduce chemicals then we hope-&-pray that the chemicals only turned on or off the things we wanted turned on or off. Craft some qualifications testing for proofs, and do a 'long-term' study to determine if there were other things turned on or off, or a short circuit occurred, or we broke something.
I sincerely hope that even without human understanding, our AI models can determine what switches are present, which ones are on and off, and how best to go about selecting for the correct result.
Right now, modern medicine is almost a complete crap-shoot. Hopefully modern AI utilities can remedy the gambling aspect of medicine discovery and use.
For example, we have a good idea of why certain antibiotics cure tuberculosis - we understand that tuberculosis is caused by certain bacteria, and we know how antibiotics affect the cellular chemistry of those bacteria to kill them. We also understand the dynamics of this, the fact that the body's immune system still has to be functioning well enough to kill many of the bacteria as well, etc. We don't fully understand all of the side-effects and possible interactions with other diseases or medications in every part of the body, but we understand the gist of it all.
Then there are drugs and diseases where we barely understand any of it. We don't have for example a clear understanding of what depression is, what the biochemistry of it is. We do know several classes of drugs that help with depression in certain individuals, but we know those drugs don't help with other individuals, and we have no way of predicting which is which. We know some of the biochemical effects of these drugs, but since we don't understand the underlying cause of depression, we don't actually know why the drugs help, or what's the difference in individuals where they don't help.
There are also widely used medications where we understand even less. Metamizole, a very widely used painkiller sold as Novalgin or Analgin and other names, discovered in 1922, has no firmly established mechanism of action.
In reality, science has already pretty much gone this way long ago, even if people don't like to admit it. Simple, reductionist explanations for complex phenomena in living systems don't really exist. Virtually all of medicine nowadays is empirical: try something, and if you can prove its safe and effective, you keep doing it. We almost never have a meaningful explanation for how it really works, and when we think we do, it gets proven wrong repeatedly, while the treatment keeps working as always.