For many philosophers, their technical philosophical work bears little or no relation to the implicit or explicit set of action-guiding beliefs and values that constitutes their worldview. Saul Kripke, for example, is an observant Jew who keeps the Sabbath and rejects naturalism and materialism. But you would never know it from his technical work which has no direct relevance to the Big Questions. (Possible qualification: the business about the necessity of identity discussed in Naming and Necessity allows for a Cartesian-style argument for mind-body dualism. See here.)
So I would characterize Kripke as a compartmentalizer. (My use of this term does not have a pejorative connotation, at least not yet.) His work in philosophy occupies one of his mental compartments while his religious convictions and practices occupy another with little or no influence of the one on the other. It is not that his technical work is inconsistent with his religious worldview; my point is that the two are largely irrelevant to each other. No doubt some of Kripke's examples 'betray' his religious upbringing -- e.g., the fascinating bit about Moloch as a misvocalization of the Hebrew 'melech' in Reference and Existence, p. 70 ff. et passim -- but his technical work, or at least his published technical work, is not a means to either the articulation or the rational justification of his worldview.
You may appreciate my point if you compare Kripke with Alvin Plantinga. He too is a religious man and a theist, an anti-naturalist, and an anti-materialist. But all of Plantinga's books that I am aware of contribute directly to the articulation and defense of his theistic worldview. He is out to explain and justify theistic belief and turn aside such objections to it as the ever-popular arguments from evil. This is clear from the titles of God and Other Minds, God, Freedom, and Evil, Does God Have a Nature. But it is also clear from Nature of Necessity the penultimate chapter of which treats of God, evil, and freedom, and the ultimate chapter of which is about God and necessity. The same is true of his two volumes on warrant one of which includes a critique of naturalism, not to mention his last book, Where the Conflict Really Lies.
The late David M. Armstrong is an interesting case. While he respects religion and is not a militant naturalist or atheist, his technical work articulates and defends his thoroughly naturalist worldview, where naturalism is the thesis that all that exists is the space-time world and its contents. The naturalist worldview comes first for Armstrong, both temporally and logically, and sets the agenda for the technical investigations of particulars, universals, states of affairs, classes, numbers, causation, laws of nature, dispositions, modality, mind, and so on. Broadly characterized, the agenda is to show how everything, including what appear to be 'abstract objects,' can be accounted for naturalistically using only those resources supplied by the natural world, without recourse to anything nonnatural or supernatural.
For Plantinga, by contrast, it is his theistic worldview that comes first both temporally and logically and sets the agenda for his technical work.
And then there is an acquaintance of mine who attends Greek Orthodox services on Sunday but during working hours is something close to a logical positivist.
This suggests a three-fold classification. There are philosophers whose
A. Technical work is consistent with but does not support their worldview;
B. Technical work is consistent with and does support their worldview;
C. Technical work is inconsistent with and hence does not support their worldview.
I will assume that (C) is an unacceptable form of compartmentalization, but I won't try to explain why in this post. Brevity is the soul of blog. This leaves (B) and (C).
Now it has always seemed obvious to me that (B) is to be preferred over (A). But do I have an argument? But first I should try to make my thesis more precise. To that end, a few more distinctions and observations.
I distinguish philosophy-as-inquiry from philosophy-as-worldview. (And you should too.) Roughly, a worldview is a more or less comprehensive system of more or less precisely articulated action-guiding beliefs and values. (Transfinite cardinal arithmetic is not a worldview: you can't 'take it to the streets.') Obviously, there are many philosophies in this sense, and therefore no such thing as philosophy in this sense. There is the philosophy of your crazy uncle who has an opinion about everything, the philosophy of Ayn Rand, the philosophy of Kant, the philosophy of Thomas Aquinas. Observe also that a philosophy in the sense of a worldview need not be arrived at by rational inquiry. Philosophy-as-inquiry, by contrast is rational inquiry by definition. To put it paradoxically, there needn't be anything philosophical about a philosophy. I trust my meaning is clear.
Note too that philosophy-as-inquiry need not result in a worldview. It can end aporetically, at an impasse, the way a number of the Platonic dialogs do, in Socratic nescience, even if the intention was to arrive at a worldview. And sometimes even the intention is lacking: there are philosophers who are content to devote their professional hours to some such narrow topic as counterfactual conditionals or epistemic closure principles, or anaphora. They can be said to engage in hyperspecialization. There are also those less extreme specialists who are concerned with ethics or epistemology but give no thought to the metaphysical presuppositions of either.
We should also distinguish between engaging in philosophy-as-inquiry in order to arrive at a worldview versus engaging in philosophy-as-inquiry in order to shore up or defend a worldview that one antecedently accepts. This is the difference between one who seeks the truth by philosophical means, a truth he does not possess, and one who possesses or thinks he possesses the truth or most of the truth and employs philosophical means to the end of defending and securing and promoting the truth that he already has and has received from some extraphilosophical source such as revelation or religious/mystical experience. The latter could be called philosophy-as-inquiry in the service of apologetics, 'apologetics' broadly construed.
It should now be evident that (B) conflates two ideas that need to be split apart. There are philosophers whose
B1. Technical work is consistent with and supports an antecedently held worldview whose source is extraphilosophical and whose source is not philosophy-as-inquiry;
B2. Technical work is consistent with and supports a worldview the source of which is philosophy-as-inquiry.
My main thesis is that (B2) is superior to (A), but I also incline to the view that (B1) is superior to (A). But for now I set aside (B1).
But why is (B2) superior to (A)? I am not saying that there is anything wrong with satisfying a purely theoretical interest either by (i) hyperspecializing and concentrating on one or a few narrow topics, or (ii) specializing as in the case of Kripke by working on a fairly wide range of topics. What I want to say is that there is something better than either of (i) or (ii).
My thesis: Since philosophy is a search for the ultimate truth about the ultimate matters, one is not true to the spirit of philosophy in the full and normative sense of the word if one is content to theorize about minutiae that in the end have no 'existential' relevance where 'existential' is to be taken in the sense of Kierkegaard, Jaspers, et. al, and their distinguished predecessors, Socrates, Augustine, Pascal, et al. One's own existence, fate, moral responsibility, and existential meaning are surely part of the ultimate matters; so to abstract from these matters by pursuing a purely theoretical interest is, if not logically absurd, then existentially absurd. In philosophy one cannot leave oneself out and be objective in the way the sciences must leave out the subject and be objective.
Of course I am not a narrow existentialist who rejects technical philosophy.
What I am maintaining is that one ought not compartmentalize: one's technical work ought to subserve a higher end, the articulation and defense of a comprehensive view of things. As Wilfrid Sellars says, "It is . . . the 'eye on the whole' which distinguishes the philosophical enterprise." (SPR 3) "The aim of philosophy, abstractly formulated, is to understand how things in the broadest possible sense of the term hang together in the broadest possible sense of the term." (SPR 1) But I am saying more than this, and words like 'view' and 'worldview' don't quite convey it since philosophy as I 'view' it ought not be purely theoretical. Somehow, oner's theory and one's Existenz need to achieve unity.
I still haven't made my thesis all that clear, but it is perhaps clear enough.
One argument for my thesis is that specialization gets us nowhere. It is notorious that philosophers have not convinced one another and that progress in philosophy has not occurred. And the best and brightest have been at it for going on three thousand years. That progress will occur in future is therefore the shakiest of inductions. Given that shakiness, it is existentially if not logically absurd to lose oneself in, say, the technical labyrinth of the philosophy of language, as fascinating as it is. Who on his deathbed will care whether reference is routed through sense or is direct? The following may help clarify my meaning.
Fred Sommers, The Logic of Natural Language (Oxford, 1982), p. xii:
My interest in Ryle's 'category mistakes' turned me away from the study of Whitehead's metaphysical writings (on which I had written a doctoral thesis at Columbia University) to the study of problems that could be arranged for possible solution.
The suggestion is that the problems of logic, but not those of metaphysics, can be "arranged for possible solution." Although I sympathize with Sommers' sentiment, he must surely have noticed that his attempt to rehabilitate pre-Fregean logical theory issues in results that are controversial, and perhaps just as controversial as the claims of metaphysicians. Or do all his colleagues in logic agree with him?
If by 'pulling in our horns' and confining ourselves to problems of language and logic we were able to attain sure and incontrovertible results, then there might well be justification for setting metaphysics aside and working on problems amenable to solution. But if it turns out that logical, linguistic, phenomenological, epistemological and all other such preliminary inquiries arrive at results that are also widely and vigorously contested, then the advantage of 'pulling in our horns' is lost and we may as well concentrate on the questions that really matter, which are most assuredly not questions of logic and language — fascinating as these may be.
Sommers' is a rich and fascinating book. But, at the end of the day, how important is it to prove that the inference embedded in 'Some girl is loved by every boy so every boy loves a girl' really is capturable, pace the dogmatic partisans of modern predicate logic, by a refurbished traditional term logic? (See pp. 144-145)
As one draws one's last breath, which is more salutary: to be worried about a silly bagatelle such as the one just mentioned, or to be contemplating God and the soul?