Post 4. Rejoinder to Gary Robertson. Gary has provided a detailed response to my second post in our written debate. Given its length, I will respond to the key arguments as follows:

Weak naturalism places the burden of proof on the supernaturalist Philosophical naturalism is not self-defeating Kalam Cosmological Argument

Weak naturalism places the burden of proof on the supernaturalist

As far as we know, the natural world is all there is. By weakening naturalism to a belief held in the absence of evidence to the contrary, weak naturalism becomes an even more formidable opponent to supernaturalism.

Weak naturalism is analogous to “weak” atheism. A weak atheist simply disbelieves in God given the lack of evidence. Weak naturalism disavows the supernatural for the same reason.

Without relying on the accepted definitions of naturalism (ie. philosophical naturalism, methodological naturalism), or of the rich philosophical history, weak naturalism is justifiable on its own terms. In only asserting the existence of the natural world, and by leaving itself open to disproof by evidence of a supernatural realm, the burden of proof is transferred to the “supernaturalist”.

Proposing weak naturalism, does not entail “appealing to the fact that nature exists rather than providing any positive evidence showing why it’s probable nothing transcends nature”. Rather, it appeals to the lack of evidence for anything supernatural, period.

Further, we might wonder what “positive evidence” could be provided for things which don’t actually exist? Things like ghosts, Big foot, or Atlantis. Surely, the lack of any evidence for said things amounts to at least a prima facie case for their nonexistence. Further, our default position should be that they don’t exist, rather than they do exist.

Now therefore, it’s up to the supernaturalist to provide evidence of the existence of a supernatural world. Where is Exhibit A? Unfortunately, the claims of the supernaturalist fall at the first hurdle.

Indeed, we should observe the special pleading routinely used to justify beliefs held sans evidence. The supernatural is defended by proposing methods of enquiry beyond the scope of empirical science. Since the supernatural is defined as being beyond the scope of the natural world, not governed by natural laws, and not measurable by science, the supernaturalist posits other means of evidence.

But this is an illegitimate move, which justifies any belief whatsoever. If this was acceptable, we would only need to claim a proposition is beyond the purview of science, and, “Voila!” we can demand equal epistemic justification for fairies, unicorns and the Loch Ness Monster. We can also keep superimposing new unseen layers upon the universe.

Further, it’s not entirely clear what this “evidence” is. In fact, it’s a circular argument seeking to justify the supernatural by inventing its own special realm of supernatural evidence. If such a realm is beyond the limits of empiricism, then it is unknowable by nature, and thus, by definition, lacks any epistemic likelihood.

We also see the appeal to immaterial realities, such as appreciation of poetry, literature, music and such, as if to suggest that these are evidence. As if things which cannot be seen, or which are not explainable by science, point to the possibility of a supernatural cloak upon reality. But we may briskly walk from the science lab over to the humanities building and see books of poetry. We can play musical instruments, read music, and even use an MRI machine to view our neurons firing as we listen. Our invisible thoughts constitute no more evidence of supernaturalism, than does the invisible operation of gravity.

Alternatively, supernaturalists seek to frame the debate in a philosophical, rather than scientific manner. In this way, the hard evidence of science can be replaced with philosophical argument: a softer approach which is satisfied by a lesser threshold for evidence.

Imagine this: We have found an incontrovertible answer to the existence of the universe. Would you be surprised if this was discovered by a team of Cosmologists? Or, theoretical physicists? Probably not.

But what if it the announcement mentioned a team of philosophers? The reason such an announcement would be greeted with derision, is that we know that without evidence, testing and verification, a claim made purely on philosophical grounds is lacking. A discovery of this type would only find general acceptance by scientific confirmation. Further, we know that it’s scientists who are working on these questions, not philosophers. They are questions of fact, not argument.

Thus, it’s not scientism to expect knowledge-claims to be verifiable, or testable. The scientific method has become the accepted method of inquiry.

Using philosophical argument, theists sometimes invoke Aquinas Five Ways or the cosmological argument to claim the universe must have had a cause, as though this was evidence. But alas, the cosmological argument is not accepted as empirical knowledge. In fact, the majority of current philosophers remain unpersuaded. Nor does the existence of the world count as “using evidence”, when invoked as a premise used to draw an illegitimate conclusion.

Weak naturalism limits itself to what we know. If there are realms which we cannot know, then there is no use in speculating upon them. The question of evidence becomes the key issue. If evidence is not measurable and knowable then it is not really evidence. And in the absence of useful evidence, it’s a false dichotomy to suggest that weak naturalism is equally likely to supernaturalism.