A quick observation about a trend in philosophical argumentation:
When a philosopher defends a view that seems to align with our immediate expectations, s/he will frequently raise something like the following, often in the introduction: this view aligns with common sense. And while it is possible for philosophy to overturn common sense, this is rare. Usually, common sense views are correct.
When a philosopher defends a view that seems counterintuitive, s/he will frequently raise something like the following point, often in the introduction: yes, this view runs counter to common sense. But sometimes radical shifts in thinking do occur, as in the Copernican revolution. It is a mistake to dismiss a view out of hand simply because it does not accord with common sense.
(I was recently reminded of the former attitude by Tyler Cowen’s Stubborn Attachments, and of the latter by Graham Priest’s In Contradiction, which, though it does not cite Copernicus, does cite scientific theories that were initially considered ‘outrageous’ and eventually accepted. I’m sure I have seen both before elsewhere.)
The two attitudes are not inconsistent. It is possible that both (1) it is rare for philosophy to overturn common sense; and (2) it is poor practice to dismiss arguments on account of their being counterintuitive. In fact, I suspect most would agree that both (1) and (2) are true.
Even so, the two attitudes do roughly pull in opposing directions. The stronger our belief in (1), the less serious we are likely to be about (2); and vice versa. What follows is a quick rant in favor of prioritizing attitude (2) over (1).
Common sense is just too damn slippery. Too often, the framing of a question can determine which answer is the ‘common sense’ answer.
Is the Liar statement meaningful?
Answer A: Well, sure it is! It’s perfectly clear what it’s saying: that it, itself, is false.
Answer B: The ‘statement’ is about nothing other than itself. There is therefore nothing for the ‘statement’ to be about—ie, there is no statement—unless we already presuppose the ‘statement’ to be a (meaningful) statement. Therefore, to assume it is meaningful begs the question.
Which is the common sense answer? For my part, I’ll take A. But why? Is it really so obvious? Certainly it is possible to present the question in such a way that B comes out looking like the common sense response.
Or take the familiar thought experiment about the doctor who can save five patients by killing one. Should she do it?
Answer A: Obviously. All else equal, it is better for one person to die than for five.
Answer B: Obviously not. Murder is wrong.
I’m not interested in which is correct; merely, which is the common sense answer? I’ll take A, but I imagine many will disagree.
Here’s one that should be easy: can contradictions be true?
Answer A: Of course not! Are you stoned?
Answer B: Natural language semantics is an emergent phenomenon, grown from of the messy interactions of primates. No one person designed, or even understands, all of English. It would be a tremendous surprise if this process yielded a perfectly consistent set of concepts.
B is, to my mind, the common sense view. Alas, it would seem my sense is not so common.
What’s going on is clear enough: because common sense is such an ambiguous and slippery concept, it’s just too easy to equivocate with it, or to simply assume your intuitions about what is common sense match those of others.
Common sense also, of course, changes with time. It was not so long ago that theism was just common sense. It wasn’t only taken on faith, but also thought to be logically self-evident. Though philosophers were willing to provide proofs, these served to shut down the stubborn skeptics, or were merely philosophical exercises. They were not generally thought necessary. After all, what else could ground the finite? What else could be the final cause? By contrast, nowadays even believers tend to either grant that theirs is an unfounded faith or accept a burden of proof.
Conversely, the ‘Copernican’ defense is too modest. Unexpected results that violate immediate expectations prop up all the time. We need not cite historically remarkable events, like major scientific revolutions, in defense of the possibility of surprise. Doing so is misleading. Surprise in inquiry is, if not the norm, at least quite far from anomaly. (Generally accepted and lasting discovery is relatively infrequent in philosophy, of course—but the tendency to reject out of hand anything that violates whatever feels like ‘common sense’ may just be one of the contributing causes to this state of affairs.)
I suspect that the impulse to overvalue ‘common sense’ and under-appreciate the possibility of surprise reflects a desire to protect philosophy from flights of speculative fancy. Given philosophy’s history, this is a reasonable concern. But we have protections from unchecked speculation: standards of rigor, precision, and argumentation. These are far from perfect, so yes, we remain vulnerable. But alignment with muddy notions of ‘common sense’ is no substitute, or even passable heuristic, for the hard work of strengthening these standards. Error by conservatism is no victory.
I’ll conclude by clarifying that this invective is directed at common sense, not intuition. Common sense means something like ‘our first intuition’. It is taking what initially appears self-evident as thereby being so. Intuition is, as far as I can tell, the only method we have for doing philosophy. All reasoning, deductive and inductive, involves following rules whose justification bottoms out at intuition. Philosophy is always a playing with intuitions: mixing them, subjecting them to each other, taking them through stages of development. Even doubts about intuition, or empirical checks on it, can only tell us something when they are subjected to intuition.
Intuition, then, is not subject to the attacks I’ve directed at common sense because intuitions can always be drawn out and developed. We can further investigate what intuition tells us about the cases I listed above. An appeal to ‘common sense’, on the other hand, is something like a call to stop the process of intuition-play at the first intuition. When that first intuition is not clear, or not shared, there’s nowhere left to go without leaving the realm of ‘common sense’.
For this reason, attachment to common sense is really something like anti-philosophy; it is taking what we start with and refusing to do the philosophy thing to it. When a philosopher says ‘that this view aligns with common sense is evidence in support of it’, she is implicitly saying something like ‘since the method of philosophy is untrustworthy, it strengthens this view that it is the one we have before we start doing philosophy’. Which, well, to be fair, maybe philosophy is untrustworthy—but give it a chance!
(Okay, fine, I admit I straw-manned the common sense position a little bit. I hope my points are illustrative nonetheless.)