One of the most popular arguments for the supernatural, emotionally weighty yet fallacious, is the notion that, if X cannot be explained by material causation, there is likely a supernatural cause. There are three reason this argument fails.
— 1: Some minds in some contexts are incapable of comprehending some explanations. This is a limitation of cognition.
Example A: The phenomenon of lighting had no material explanation at one time, and was co-opted by supernaturalists as evidence for a supernatural realm. The explanatory scope of science and the depth of cognitive power in most individuals at that time made a scientific explanation of this phenomenon impossible. Was it proper for humans at that stage of human understanding to default to a supernatural explanation such as an exhibition of the disapproval of some God? Or should they have simply and honestly said “we do not know”?
Example B: A child or mentally challenged individual cannot comprehend the notion that a beloved dead pet no longer exists in any realm. Their minds simply don’t have the capacity to conceive of non-existence. To conclude from this lack of conceptual power that the pets must continue to exist in an immaterial world is fallacious.
Example C: It is difficult for unschooled human minds to deal with scopes of size and time that are not common to mundane human scopes of activity. The notion of incremental changes over time of millions of years in respect to evolution or the formation of mountains is not easy for the untrained mind to grasp. A specific one-in-a-million event within the trillions of events that have happened over time is unsurprising, but considered miraculous by those unable to grasp the enormity of the space of events. Untrained minds have quickly defaulted to the notion that a supernatural force is at work when it is simply their cognition that is not at work to the degree necessary for comprehension.
— 2: Language is intrinsically limited, and this linguistic limitation often fools humans into thinking what is ineffable is evidence of something supernatural.
Example A: Human languages cannot describe the deep essence of quantum superposition or entanglement. Scientists content themselves with describing merely the results of the experiments since their is no semantically adequate framework available to satisfactorily describe the causal dynamics and underlying concepts that would accomplish understanding. (This linguistic failure may, admittedly, be wholly emergent of the cognitive failure of humans minds to conceptually grasp these concepts. Where you have comprehensible concepts, there you’ll usually have soon following a jargon to effectively express those concepts. You’ll have to take that up with physicists.)
— 3: Some questions are conceptually illegitimate. This is the most important point here.
Example A: The fact that we cannot scientifically explain the jealousy of monkeys does not mean their jealousy requires a supernatural realm in which to operate. The claim “You can not explain love” (or any other emotion) as a defense of the supernatural is illegitimate. Science operates on the objective side, intrinsically external to subjectivity, while subjective feelings (qualia) are experienced in a domain inaccessible to the descriptive power of objective science. This essential division does not suggest subjectivity is not wholly dependent on and emergent of an material substrate. To ask how subjective sensations can emerge if there is only a material world is to ask an illegitimate question since the dynamics of the brain, for example, are experienced subjectively, not objectively, in the subjective mind.
Example B: We experience the material wavelengths of light in different ways. The fact that colorblindness reduces two different wavelengths into one perceived color does not mean there is no longer two different wavelengths. The objective world is ontologically prior rather than our subjectivity. Subjective experiences do not require a supernatural substrate on which to operate since the material substrate is more than adequate. It is like asking for a satisfactory scientific description of the smell of roses, and when met with silence, claiming smells must therefore occupy a supernatural realm.
— How might a supernatural realm (in which no material causes are behind certain phenomena) be demonstrated? Here are a couple ideas.
1. Near-death experiences. This has been recently invoked by many apologists, but it appears all such claims are either a) limited to one subjective experience (and recantation: https://www.theguardian.com/books/2015/jan/21/boy-who-came-back-from-heaven-alex-malarkey) and replete with conceptual inconsistencies such as the manifestation of various Gods, devils, Heavens and Hells.
2. Because the material realm is commonly understood to be limited to physically and temporally bound causation, demonstrating causation that transcends these physical and temporal limitations would be a good start. If mental thoughts stop aligning with brain processes, perhaps then we can begin entertaining supernatural explanations. We currently observe a high correlation between brain states and mental states that only increases as we untangle the workings of the brain.
The central point is that we don’t, if we are rational, default to the notion of a spiritual realm when encountering no explanation on an emotionally unsatisfactory explanation for mental phenomena that, by their very nature, are not accessible to the realm of scientific explanation. The emergence of subjectivity from objectivity does not warrant the claim that the supernatural must therefore exist, especially given the highly correlative ties between brain states and mental states.