In defence of weak naturalism – Post 2: a response to Gary Robertson

In defence of weak naturalism – Post 2: a response to Gary Robertson’s Is Naturalism more probable than Supernaturalism?

by Hugh Harris


The position I propose to defend is weak naturalism. Conforming broadly to the standard of scientific inquiry known as methodological naturalism, it can be distinguished from the stronger position of philosophical naturalism, which claims categorically that the natural world is all there is.

Weak naturalism: as far as we know, the natural world is all there is. I defend the claim that naturalism is more probable than supernaturalism, in my essay Naturalism versus Supernaturalism- the false dichotomy – I argue that the observance of the natural world along with its laws combined with the absence of any evidence of the supernatural, amounts to a strong prima facie case for naturalism, and its likelihood in comparison to the sans-evidence claims of supernaturalism.

In his first post, Is Naturalism more probable than Supernaturalism?, Gary Robertson seems to exclude science from the debate, only to later revive it to provide the foundation for the kalam cosmological argument. Gary states that “Methodological naturalism restricts scientific enquiry to the study of natural causes and processes”, thus, “methods of enquiry into the existence of a supernatural reality are beyond the scope of empirical science”, and thus, “all propositions about ultimate reality will necessarily be philosophical”. I’m not sure why Gary does this, but I suspect that it’s so he can trade off the equality between the definitions of naturalism and supernaturalism . Perhaps philosophically they are equal inversions, in the sense that naturalism is the denial of the supernatural and the supernatural is the affirmation of it. But evidentially, they are not equal.

Virtually all scientists operate under the assumption of philosophical naturalism – all causes are empirical and naturalistic ones which can be measured, quantified and studied methodically. When our children are ill, we don’t look for magicians or witch doctors summoning supernatural forces. Why? Because there is no evidence they work, and much evidence suggesting they’re harmful. And this is despite the plethora of religious faith healers such as the discredited John of God faith healer, who scratches at the eyes of the credulous and who has made over $10 million out of selling crystals and other fake cures, and yet, had his own cancer treated by chemotherapy in a hospital.

And so Gary might have to forgive my reluctance to sideline science altogether from this debate. Additionally, I assume we’d agree that philosophy cannot exist in its own bubble, separated from empiricism, with no regard for the real world. Ontological naturalism is indeed a philosophical position, but as a study of the ultimate nature of reality it cannot be simply hived out and segregated from science. Further, the ultimate nature of reality is unlikely to vary depending on what University faculty building one happens to be in.

Evidently Gary agrees, given he goes on to claim that “supernatural causation logically follows from empirical evidence in the field of cosmology that strongly suggests the universe had a beginning and that nature…did not exist prior to the universe coming into being. Thus, … the universe transcended nature and was, therefore, supernatural”.

But I disagree that that’s what the scientific/empirical evidence suggests, as indeed do the majority of philosophers and scientists. The kalam cosmological argument:


Whatever begins to exist has a cause.

The Universe began to exist.

Therefore, the Universe had a cause


Objecting to my previous critique, Gary issues the following challenge: “I would certainly be keen to know how the deductive arguments formulated above equate to “conflating the process of coming to an invalid conclusion using empirical evidence rather than simply observing the empirical evidence itself””.

The cosmological argument uses the causality, we observe in the known world to make the case that the known world itself must have a cause. But this self-referentially uses the laws of causality, to explain their own existence. Bertrand Russell exposes that moving from the contingency of the components of the universe, to the contingency of the universe, commits the Fallacy of Composition, which mistakenly concludes that since the parts have a certain property, the whole likewise has that property. If all bricks in a wall are small, is the Great Wall of China small?

The kalam cosmological argument makes the invalid assumption the universe began to exist. Given that space and time are inextricably linked, the contention that the universe began suggests a moment preceding its existence. But, as Stephen Hawking has pointed out, this is like seeking a point more northerly than the North Pole – the universe can be both finite and without a prior moment or beginning.

Adolf Grunbaum 1994, explains that the singularity of the Big Bang does not conform to an actual “physical event” given its unbounded nature, infinite density and scalar curvature. Thus, it does not even have the requisite chrono-geometric relations specified by the space-time metric, to which a cause could be applied – it cannot in fact “be the effect of event-causation or agent-causation alike”.

Additionally, the laws of conservation do not suggest that we can keep on subtracting elements from the universe until we get nothing. Parmenides famous adage, “from nothing, nothing comes”, does not suggest that nothing preceded something and that something needs a cause. Rather, it expresses the riddle of existence itself. There is no reduction of something into nothing in the natural world. And so, the state of nothing which is supposed to precede something, is doubtful at best, and antithetical to our observations of the natural world at worst.

Grunbaum 1994, further argues that “a galaxy of theists… take it to be axiomatic that if there is a physical world at all, then its spontaneous, undisturbed or natural state is one of utter nothingness, whatever that is… Why, in the absence of an external supernatural cause, should there be just nothing?” Further, the “presupposition of the spontaneity of nothingness lacks even the most rudimentary plausibility”. Many philosophers have argued against the proposition of nothingness as unintelligible. Why assume nothingness as a default, or a brute fact?

The other consideration, is that the cosmological argument assumes the universe itself cannot be a brute fact (or eternal) because everything that begins must have a cause; and then goes on to suggest that therefore there must be a brute fact (such as God) to explain it. This is begging the question. One cannot logically deny the existence of brute facts as a premise (whatever begins to exist has a cause) and then insert a brute fact as the conclusion (a necessary, uncaused being). One can simply ask why can’t the universe, or an element within it, be the brute fact. Crucially, even if one accepts that the universe begins, why cannot it not begin due to a timeless natural force which governs all of existence?

Thus, it’s invalid to suggest that the evidence points to a supernatural cause of the universe. In regards to teleological arguments we’ll have to discuss the specific versions. Then, my generalisations on this subject – “arguments from incredulity” – can be supported by considering the particular teleological argument in question.