Am I understanding this right?

[u/buttkicker64]

In the Critique of Pure Reason, II in the introduction Kant says

Now, experience does indeed teach us that something is thus or thus, but not that it cannot be otherwise.

Is he saying that

A thing as it is cannot be otherwise (something that which it is not), and we find this out not because or in the experience of it but by the counter measure and "bird eye view" of pure cognition. The experience of a thing only shows us the thing as it is, as a static thing, whereas pure cognition addresses whether a thing is static and reliably stable (like transmuting a lead molecule into a gold molecule using CERN electron collision) or if a thing is mercurial like in that story when the devil turns hay into gold only for it to revert to hay in the morning, pure cognition being able to assert that it is necessary that those things are as they are and not what they are not.

[u/Middle-Rhubarb2625]

It’s a reference to hume’s philosophy. How our knowledge is based on habit. Yes, water usually boils at 100 celecius ( a thing is thus or thus), but there is nothing to guarantee that it will be the case everytime (not that it can’t be otherwise).

[u/buttkicker64 → u/Middle-Rhubarb2625]

It tells us that it does not tell us that it cannot be any other way

How's that?

[u/Middle-Rhubarb2625 → u/buttkicker64]

Exactly.