When I spoke about this to Jon last night, he said, "Why not just say 'cf. Hume' and call it a day".
Good point, Jon; I could.
The thing is that there are tons of Naturalistic Atheists who cleave to Hume and yet go on to make positive claims about causation.
And then again even in a psychology class I took in college from a professor who was most certainly not a Naturalistic Atheist, he pressed the point home that correlation does not imply causation (he spoke about the correlation of popsicle consumption and drownings as an example), and then he went on to show the types of things that do imply causation.
But on what grounds? He and everyone else just beg the question and push each matter back a notch whenever they speak of some X causing some Y.
So instead of saying "cf. Hume", I am choosing to say "hey I realized that nobody has solved Hume yet (cf. Hume), and yet we brazenly make claims about causation, and this seems quirky.".
*For all inferences from experience suppose as their foundation that the future will resemble the past and that similar powers will be conjoined with similar qualities. If there is any suspicion that the course of nature may change, and that the past may be no rule for the future, all experience becomes useless and can give rise to no inference of conclusion. It is impossible, therefore, that any arguments from experience can prove this resemblance of the past to the future, since all these arguments are founded on the supposition of that resemblance. Let the course of things be allowed up to now ever so regular, that alone, without some new argument of inference, does not prove that for the future it will continue so. In vain do you pretend to have learned the nature of bodies from your past experience. Their secret nature and, consequently, all their effects and influence may change without any change in their sensible qualities. This happens sometimes and with regard to some objects. Why may it not happen always and with regard to all objects? What logic, what process of argument secures you against this supposition? My practice, you say, refutes my doubts. But you mistake the purport of my question. As an agent, I am quite satisfied in the point, but as a philosopher who has some share of curiosity--I will not say skepticism--I want to learn the foundation of this inference. No reading, no inquiry has yet been able to remove my difficulty or give me satisfaction in a matter of such importance.
- David Hume. An Inquiry Concerning Human Understanding, Section IV: Part II.