[Haskell-cafe] Questions for Free!

[Creighton Hogg]

Hello Haskellers,
So I have a bit of a follow up question after reading Theorems For
Free! this weekend.
There's a throw away comment near the beginning about how you can
recast the results into category theoretic form, but using lax natural
transformations.
Now I'm assuming this means a natural transformation but where the
"naturality" square holds only up to isomorphism instead of equality,
but is that correct?  Also, why would you need such a condition?

Cheers,
Creighton