>Explaining something like gravity doesn't try to justify why it is that way, it only shows that we understand it in depth.
So clearly there's some disagreement here about what "explain" means, so I'll avoid that semantic argument and skip to the point:
Understanding something "in depth" is not necessary for science. As long as a shallow understanding makes accurate predictions, it is scientific. Trying to make more detailed rules would just be violating Occam's Razor.
To get back to the original point: If we make the hypothesis "Ketamine cures depression" and find no evidence to the contrary, then it is a theory which is sufficient to describe the world, and speculation about the mechanism is a pointless exercise, just as it would be pointless to look for a more complicated theory of gravity to describe things adequately explained by GR.
However, if we were to find (as is more likely) that in some cases Ketamine doesn't cure depression, only then is there a reason to delve deeper to work out why.
So clearly there's some disagreement here about what "explain" means, so I'll avoid that semantic argument and skip to the point:
Understanding something "in depth" is not necessary for science. As long as a shallow understanding makes accurate predictions, it is scientific. Trying to make more detailed rules would just be violating Occam's Razor.
To get back to the original point: If we make the hypothesis "Ketamine cures depression" and find no evidence to the contrary, then it is a theory which is sufficient to describe the world, and speculation about the mechanism is a pointless exercise, just as it would be pointless to look for a more complicated theory of gravity to describe things adequately explained by GR.
However, if we were to find (as is more likely) that in some cases Ketamine doesn't cure depression, only then is there a reason to delve deeper to work out why.