How about wombats? Skipjack tuna? Rhinoceros beetles? Ganoderma mushrooms? Sugar maples? Cold-hardy lichens? E. coli bacteria?
Many Christian apologists, at least since John Calvin cooked it up (applying it only to humans), rely upon such a hypothetical "sense," called sensus divinitatis, to claim that knowledge of God is possible. Calvin asserted on the basis of this sense that there are no true atheists, in fact.
More reasonably, the famed Christian philosopher Alvin Plantinga has made a solid philosophical argument that if the sensus divinitatus exists, then it would provide a reasonable basis upon which to claim knowledge of God. From where I sit, then, it seems to be the case that Calvin, thus Plantinga and legions of other apologists, seek to support the possibility of knowledge of a hypothetical God by positing a hypothetical sense. Put another way, they're saying "if we have this special sense, then we can claim knowledge of God, and you can't prove we don't have it." Sound familiar?
The thing is, it's not up to anyone to prove that we don't have some hypothetical, possibly imaginary sense. It's up to its proponents to prove that we do have it. And that brings me back to my opening questions. Calvin asserted an answer in the negative, and the usual conception of the sensus divinitatis applies only to humans. I don't know how they can know this (actually, I strongly suspect they cannot know this), so I won't simply assume it. This claim, widely made of the sense, paves a road to proving its existence--one they should walk if they want to be taken seriously. What I want to do, then, is give them an opportunity to put legs under their fancy.
As someone who doesn't believe the ravings of theologians unless those happen to be supported by evidence, I often get accused of having unreasonable or even impossible standards of evidence regarding theological matters. This could not be further from the truth. My standards of evidence are certainly not impossible--given credible evidence for any claim, I will embrace acceptance of it in immediate proportion to the confidence warranted to it by the evidence--and they are certainly reasonable for that reason. The sensus divinitatis is a theological claim, so here I'll lay out some initial evidential considerations that would tip me toward accepting it.
There are three related possibilities (and a fourth, for exhaustion of all possibilities).
- John Calvin, et al., are right, and the sensus divinitatis applies only to humans.
- John Calvin, et al., are mistaken on this point and some, but not all, of the phylogenic tree possesses the sensus divinitatis.
- John Calvin, et al., are mistaken on this point and all of the phylogenic tree possesses the sensus divinitatis.
Cases (1) and (2)--Some life, perhaps only humans, has the sensus divinitatis
In this case, somewhere on the full tree of life, a branch arose in which the sensus divinitatis, theretofore nonexistent, first arose. Though I am not a biologist, I know enough biology to know that we know how such things work: mutations on a certain gene or genes gave rise to a radical functional change in the descendents from that point on. This is evolution; this is biology; and this is not controversial in the least.
That should indicate that if the sensus divinitatis exists in some life but not others, there should be some identifiable gene mutation that enables its existence. Thus, in principle, it should be detectable. If humans have it but chimps do not, for instance, it would be a matter of seeking the relevant mutant allele in the human genome. If all primates or mammals have it, but the rest do not, it would simply be a matter of looking across genera, families, orders, classes, phyla, kingdoms, or domains, as applicable.
In this case, we face the fortunate situation in which one of our common ancestors along the line evolved this sense. I call this a fortunate situation because, if it were true, it would allow us to give a pretty good approximate date for when the mutation occurred, thus when God first allowed himself to be detected by what gets called "his creation." What a fascinating bit of knowledge that would be!
Christian philosopher Alvin Plantinga, if he is right, may have made it even easier to look for since he asserts that the sensus divinitatis for some reasons does not work in particular people. It should be a straightforward matter, then, at least in principle, to start checking for such a mutation: some people who claim to have the sensus divinitatis should have the relevant gene turned on while at least some people who do not seem to have it should have it turned off.
If such a thing is ever found, standing up to the battery of cautious investigation that scientists demand, thereby meriting a high level of statistical confidence supporting it, then I will give serious consideration to the idea of a sensus divinitatis, in proportion to the warrant of evidence supporting it, of course.
Case (3)--All life has the sensus divinitatis
I'll be candid before investigating this: I really look forward to any theological argument attempting to assert that moss and pinworms have an operating sense of the divine. Hilarity will ensue, however frustrating.
I'll also note that even here, there should be an identifiable gene, universal to all life, that enables such a sense to exist and operate. In principle, this gene is identifiable, though it may be significantly harder to find without knowing exactly how to draw comparisons across species "known" to differ on this matter.
The more accessible place to look, though, in this case, is for a universal sense organ that makes the sensus divinitatis work. No doubt in humans, that sense organ is connected to (or part of) the brain. (Many mystics, in fact, would assert that it is the pineal gland in the core of the brain.) This raises a fascinating question about how lifeforms without brains, for example flowering dogwood trees and dog vomit slime mold, manifest the sensus divinitatis, and what organs or structures are actually responsible for it.
If such a universal organ/structure and/or mechanism is ever found, standing up to the battery of cautious investigation that scientists demand, thereby meriting a high level of statistical confidence supporting it, then I will give serious consideration to the idea of a sensus divinitatis, in proportion to the warrant of evidence supporting it, of course.
Case (4)--The sensus divinitatis is magic
No elaboration is needed here. In this case, there is not sufficient evidence to warrant serious consideration of the sensus divinitatis, and everyone talking about it really should just shut up about it.
Edit, Jan 3: It has been brought to my attention that attempting to identify sensus divinitatis with a particular gene, group of genes, or even phenotype may be a biologically bad way to make my point (Cf. phenotypic plasticity). My intention and argument doesn't depend upon genes, inter alia, but rather on there being some kind of physical evidence (hopefully a physical structure of some kind) for such a sense being required for me to consider it a credible claim. Without such evidence, I see appeals to a sensus divinitatis as being a statement of "if it existed, it would justify knowledge of God, and you can't prove it doesn't exist."
I base this requirement on the fact that so far as I can tell, any such sense ultimately has to interface with the brain to make an actual knowledge claim about it. Since the brain is a physical thing whose structure intimately depends in some way upon genetic expression, I used the notion of genes (particularly since it is most fitting if we are going to compare such a sense in humans that doesn't exist in any other animals or lifeforms).
It was not my intention to mislead people into thinking things like gene X leads to consequence Y, and for any of that, I apologize.
Further, I should disclaim that such a scientific undertaking at present is unlikely to be "easy," but in principle (and in 50 years) it very well may be.