There are two different attitudes that I will call "approaches of diffidence" that Christians who are philosophers can take. One is more extreme than the other. Both are wrong.
Attitude #1 is what I will call the Averroist Approach. The Averroist Approach says that, to be an honest and professional philosopher, you must even in your own mind completely bracket your Christian beliefs when you are doing philosophy. So, for example, if you are examining the question of the existence of a non-material aspect to man, you should bracket the fact that traditional Christianity clearly does assume that there is such a thing (hint: "the soul"). That's religion, not philosophy. The two are different, and that's flat. They just don't have anything to do with one another, and the fact that you believe Christianity to be true can't give you any reason, while you happen to have your philosopher's hat on your head, for believing in the existence of the soul.
My reasons for connecting this approach with Averroes should be historically evident.
Attitude #2 is what I will call Extreme Rhetorical Diffidence. ERD says that even though in the privacy of their own minds Christian philosophers do believe things at odds with the zeitgeist, when it comes to making arguments, they have to pretend for practical purposes that they don't. In fact, the best rhetorical thing to do is to assume, for the sake of the argument, the truth of the most popular present philosophical position, even if that is not only totally at odds with your Christian beliefs but also at odds with other known and developed philosophical options. Hence, even though there are non-Christians (or philosophers who don't make use of explicitly Christian premises) who question or outright deny naturalism, use only naturalist premises when making your arguments--say, in ethics. Even though there have been secular humanist philosophers who have rejected Peter Singer (e.g., Jenny Teichman), use only Singer-approved premises when doing ethics. Even though neo-Aristotelians like David Oderberg defend essences, assume nominalism in metaphysics. Even though Richard Fumerton is an internalist in epistemology, don't question naturalized epistemology and externalism. Even though Thomas Nagel strongly questions materialism, don't challenge the premise that the mind evolved by purely material means. And so forth.
Do I exaggerate? Maybe a little. But if you know a lot of Christian philosophers, especially those just getting started, I'll wager you've met at least a couple who take positions enough like these that my characterizations are recognizable.
There are many streams that feed into the river of conformism. At the risk of offending, I cannot refrain from saying that one stream is fear. But that may not influence everybody, and I'd rather focus on others. I truly believe that Christian philosophers face difficulty knowing what it means to be both Christian and professional in philosophy. The philosophical establishment tells them that religion is unprofessional and then ups the ante yet further by telling them that all manner of unpopular positions, including positions that didn't used to be thought to be religious, are actually religious, tainted with religion, indefensible except by resort to explicitly religious premises, etc. The effect is heightened by simply not teaching alternative views, so that dualisms of various sorts are dismissed contemptuously in metaphysics class, and graduate epistemology class is all about "naturalized epistemology," even though that is a relatively recent phenomenon.
As for ethics, don't get me started. I've already said plenty elsewhere. (For just a few examples, see here, here, and here.) See also this 2008 article by David S. Oderberg. Let's face it: Professional rewards go to those who write articles conspicuously lacking in philosophical merit that simply push the envelope further after starting with, say, Michael Tooley's infanticidal assumptions as a given. I don't actually look at the syllabuses of graduate and undergraduate ethics courses in America, but I think it would be interesting to ask: When was the last time Teichman was required reading? (I'll be happy to be proved wrong in guessing, "Not very often." If so, of course, that just means there is less excuse for Extreme Rhetorical Diffidence in challenging Singer.)
It's little wonder that young philosophers get the impression that they are violating professional norms if they don't a) set aside their Christian beliefs and b) make arguments only from popular stances.
In fact, though, Averroism is false. There is only one truth. If Christianity is true, then its teachings and clear implications are entirely compatible with the conclusions of true philosophy. More: Christianity is defensible by evidence. If anything should stiffen your spine, that should. Your Christianity doesn't have to be some private little intellectual vice that you can't quite give up, something you hold to because of your upbringing, something foggy, fuzzy, and mystical. You need not be ashamed of your Christianity before your hard-edged philosopher friends. Man up. Not only is Christianity true, but God has not left himself without witness.
If you are a Christian and you insist on setting aside your Christian beliefs in developing your own philosophical beliefs, you are at grave risk of developing a split mind, an Averroist mind, a mind that believes incompatible things. You are at risk of denying the unity of truth, in practice if not in theory. And, since intellectual people find it hard to live that way, and since as a philosopher you will be surrounded by smart, sophisticated atheist and agnostic colleagues, you are at risk of losing your faith altogether. Not a good position to be in.
Ah, but what about ERD? After all, it's a long way roundabout to argue for, say, a non-materialist view of the human person by first arguing for Christianity per se, evidence or no. I agree. It is a long way roundabout, nor do I recommend it.
Here is where we need to focus again on the concept of the integrated mind, and the integrated world. Do we as Christians really believe that the notion of, say, human nature is inaccessible to non-Christians? Do we believe that the idea that it is wrong to murder human infants is something that can be grasped only by a rote adherence to a Divine command? What about the existence of the mind? Did man really not know that he had a mind until God revealed this, so that the only way to tell philosophers reasonably that they have minds is by arguing from explicitly religious premises?
The Averroist Approach is obviously dis-integrated. But the Extreme Rhetorical Diffidence approach also fosters a dis-integrated mind. Let's talk as Christian to Christian. We believe that man is made in the image of God, that God has given general revelation, and that God has written his law on man's heart, a law for which all men are responsible. It hardly seems a long stretch to take this to mean that God has given man access to such commonsensical propositions as
--Man is not merely a material entity,
--There is such a thing as objective truth,
--There really is such a thing as a human species and a human nature,
--Human beings have value simply in virtue of their humanity,
--It is wrong deliberately to kill human infants,
--Men and women are different from each other.
--I have access to my own thoughts and experiences, which are not just material phenomena.
Suppose that we start out by thinking that these propositions are just so inaccessible and so controversial that all our arguments must treat them as false, or at least that we must never start from the assumption that one of them is true. It seems that in doing so we are treating the image of God in man and general revelation as having no or virtually no intellectual consequences or content. Epistemically, we are treating these things as if they are very, very difficult to see to be true, as though they were all highly complex, abstract mathematical conclusions. And what consequences does that assumption have for the robustness of our own positions on these issues? If you really think that "Man is a rational animal" (a proposition whose philosophical credentials ought to be assured) and other propositions in the vicinity are only Divinely revealed black boxes, outlandish, alien, and counterintuitive conclusions which you accept only because God told you they are true, how likely is it that you will stick to them in the face of continual assaults from feminists, physicalists, and postmodernists?
Note, too, what ERD appears to concede, unjustifiedly, about burden of proof. Apparently Singer & Co. can blithely assume that "personhood" is the kind of thing that comes and goes in a human life. This despite not only the monstrous conclusions to which that position leads (which should be reductios in themselves) but also the difficulties it faces with deep sleep or induced dreamless unconsciousness. One assumes that a personhood theorist would believe that a wrong had been done him if he were killed for his organs without his consent after being thoroughly knocked out for, say, hip replacement surgery. (Thus being temporarily turned into a "non-person," right?) Yet the ERD approach would lead us to treat Singeresque personhood theory as the default position because of its popularity--a dangerous move toward making the bandwagon fallacy a principle of philosophical debate.
The Christian who advocates something like ERD might respond that one's faith in, say, the Trinity is not shaky simply because one regards it as a truth of revelation rather than a truth of nature. And it certainly seems that the specific doctrines of Christianity--the deity of Christ, the Trinity, the resurrection, and the like--bear some sort of burden of proof. So what is the problem with extending that approach to other, more general philosophical propositions?
The answer ought to be fairly evident. Aquinas told us long ago that grace builds on nature. The problem with the ERD approach is that it functionally assumes that there is, epistemically speaking, no nature to build on. In so doing, the Christian philosopher underrates and thus undermines not only the human nature of his non-Christian opponents but his own human nature as well.
In the introduction to The Revenge of Conscience, Jay Budziszewski tells of a time when he was, as he puts it, looking into himself and tearing out everything that had the image of God on it.
Visualize a man opening up the access panels of his mind and pulling out all the components that have God's image stamped on them. The problem is that they all have God's image stamped on them, so the man can never stop. No matter how much he pulls out, there's still more to pull. I was that man. Because I pulled out more and more, there was less and less that I could think about. But because there was less and less that I could think about, I thought I was becoming more and more focused. Because I believed things that filled me with dread, I thought I was smarter and braver than the people who didn't believe them. I thought I saw an emptiness at the heart of the universe that was hidden from their foolish eyes. Of course I was the fool....There is a point of no return, and I was almost there. I said I had been pulling out one component after another, and I had nearly got, shall we say, to the motherboard.If we tear out all the pieces stamped "image of God," we leave ourselves with nothing. The proponent of ERD apparently thinks that unbelievers, because they do not accept special revelation, really cannot be expected to know, e.g., that there is anything wrong with killing human infants or that there is such a thing as human nature. Unfortunately, this goes near to implying that tearing out the motherboard, for unbelievers, is justified.
The Revenge of Conscience, pp. xv-xvi
About two years ago I wrote this post on Alvin Plantinga's interesting paper, "Advice to Christian Philosophers." In my post I expressed agreement with much of what Plantinga said and some disagreements. Here I want to emphasize the agreements. Plantinga's idea of "integrality" is very similar to what I have been calling "the integrated mind." Plantinga says,
Second, Christian philosophers must display more integrity-integrity in the sense of integral wholeness, or oneness, or unity, being all of one piece. Perhaps 'integrality' would be the better word here.
And he gives a couple of rather amusing examples:
Suppose the student I mentioned above goes to Harvard; she studies with Willard van Orman Quine. She finds herself attracted to Quine's programs and procedures: his radical empiricism, his allegiance to natural science, his inclination towards behaviorism, his uncompromising naturalism, and his taste for desert landscapes and ontological parsimony. It would be wholly natural for her to become totally involved in these projects and programs, to come to think of fruitful and worthwhile philosophy as substantially circumscribed by them. Of course she will note certain tensions between her Christian belief and her way of practicing philosophy; and she may then bend her efforts to putting the two together, to harmonizing them. She may devote her time and energy to seeing how one might understand or reinterpret Christian belief in such a way as to be palatable to the Quinian. One philosopher I know, embarking on just such a project, suggested that Christians should think of God as a set (Quine is prepared to countenance sets): the set of all true propositions, perhaps, or the set of right actions, or the union of those sets, or perhaps their Cartesian product. This is understandable; but it is also profoundly misdirected. Quine is a marvelously gifted philosopher: a subtle, original and powerful philosophical force. But his fundamental commitments, his fundamental projects and concerns, are wholly different from those of the Christian community--wholly different and, indeed, antithetical to them. And the result of attempting to graft Christian thought onto his basic view of the world will be at best an unintegral pastiche; at worst it will seriously compromise, or distort, or trivialize the claims of Christian theism. What is needed here is more wholeness, more integrality.
By now, of course, Verificationism has retreated into the obscurity it so richly deserves; but the moral remains. This hand wringing and those attempts to accommodate the positivist were wholly inappropriate. I realize that hindsight is clearer than foresight and I do not recount this bit of recent intellectual history in order to be critical of my elders or to claim that we are wiser than our fathers: what I want to point out is that we can learn something from the whole nasty incident. For Christian philosophers should have adopted a quite different attitude towards positivism and its verifiability criterion. What they should have said to the positivists is: "Your criterion is mistaken: for such statements as 'God loves us' and 'God created the heavens and the earth' are clearly meaningful; so if they aren't verifiable in your sense, then it is false that all and only statements verifiable in that sense are meaningful." What was needed here was less accommodation to current fashion and more Christian self-confidence: Christian theism is true; if Christian theism is true, then the verifiability criterion is false; so the verifiability criterion is false. Of course, if the verificationists had given cogent arguments for their criterion, from premises that had some legitimate claim on Christian or theistic thinkers, then perhaps there would have been a problem here for the Christian philosopher; then we would have been obliged either to agree that Christian theism is cognitively meaningless, or else revise or reject those premises. But the Verificationists never gave any cogent arguments; indeed, they seldom gave any arguments at all. Some simply trumpeted this principle as a great discovery, and when challenged, repeated it loudly and slowly; but why should that disturb anyone? Others proposed it as a definition--a definition of the term "meaningful." Now of course the positivists had a right to use this term in any way they chose; it's a free country. But how could their decision to use that term in a particular way show anything so momentous as that all those who took themselves to be believers in God were wholly deluded? If I propose to use the term 'Democrat' to mean 'unmitigated scoundrel,' would it follow that Democrats everywhere should hang their heads in shame? And my point, to repeat myself, is that Christian philosophers should have displayed more integrity, more independence, less readiness to trim their sails to the prevailing philosophical winds of doctrine, and more Christian self-confidence.
The examples I have used above are different from Plantinga's, but the point is the same.The assumptions of the philosophical zeitgeist are very often simply wrong, not to mention silly, and sometimes outright monstrous. Bearing that in mind, don't force yourself to make your arguments only within the confines of those assumptions.
Instead, be a Christian philosopher with an integrated mind.
P.S. In the very interesting discussion that followed my previous post, philosopher Bobcat answered my call for a list of non-Christian philosophers who hold unpopular philosophical positions, positions that call naturalism into question. In addition to those I mentioned above, here are those lists from Bobcat:
Carl Ginet: non-agent-causal libertarian; Bob Brandom: non-naturalist who I assume is an atheist; John McDowell: same as Brandom; William Rowe: agent-causal libertarian; W.D. Hart: I believe he is a substance dualist; David Chalmers: property dualist or panpsychist
Paul Draper: agent-causal libertarian (I think); Michael Huemer: substance dualist/agent-causal libertarian/moral realist; Don Regan: non-naturalist moral realist; Russ Shafer-Landau: non-naturalist moral realist; Jaegwon Kim: flirting with property dualism.
And here is a post on "old-time atheist" anti-materialists from Ed Feser.