A Simple Argument against Simple Arguments

Take X to be some view; take Y to be some simple and obvious objection to that view that is either based on internal coherence or facts that everybody accepts.

1. If X is accepted by many philosophers and/or taken seriously even by philosophers who reject X, then, Y should not be seen as a defeater for X.
2. The antecedent of (1) is true.
3. Therefore, the consequent of (1) is true.

On (1), the reason why is this. If X were open to obvious defeat, then it is doubtful that many philosophers would accept it and even less doubtful that philosophers who reject X would take it seriously (it is open to simple and obvious refutation after all!). Now, this does not mean that Y does not defeat X, only that it is most likely the case that Y defeats X only by defeating the defeater given for Y (or something even more intricate!). None of this, of course, entails that X isn’t open to obvious refutation by Y, only that we would be out of bound epistemically in thinking so (this last clause is intentionally vague as I think the idea as a whole can be communicated without needing to nitpick details). For those who think the premise is too strong as is, one can add a “probably” after “then” and achieve much of the same result.
On (2), no claim is actually being made here, but if some person would want to propose some position as X, then they would have to defend it.
(3) follows.

My Hands Disprove Empiricism

Consider the following argument:

(1)  If empiricism is true, then any synthetic belief is open to revision.
(2)  At least one synthetic belief is not open to revision.
(3)  Therefore, empiricism is false.

The argument is valid because it follows a standard modus tollens.  Thus, we must look at the premises.

As to (1), if a belief is synthetic then it can in theory be falsified.  For instance, Newton’s law of universal gravitation had a ton of support for it, but there were phenomena that showed Newton’s law to be incorrect and so it was abandoned.  The same is true of any other belief under empiricism since a fact that falsifies the belief would lead one to revise the belief.  Now this doesn’t mean that any anomaly must cause belief revision since Kuhn has pointed out that every theory faces anomalies, but that fact does not falsify (1).

As to (2), consider this argument for it:

(4)  At least one synthetic belief is of such a nature that it has an intrinsic defeater-defeater.
(5)  If a belief has an intrinsic defeater-defeater, then it is not open to revision.
(2)  Therefore, at least one synthetic belief is not open to revision.

Again, the argument is logically valid by means of modus ponens so we must look at the premises to see whether they are true.

As to (4), examples seem to abound of this sort.  If Quine is right that there are no such things as analytic truths, then something like “there are no married bachelors” or “if p, then p” would be great examples.  However, if we think Quine is wrong on that matter, then there are other examples still.  Consider Moore’s famous argument about his two hands: “here is one hand, and here is another.”  Now what could defeat my knowledge that I have two hands?  If I seem to wake up and find myself with only one hand, then I would suppose that a brief bit of my memory was about a dream within a dream and so I am still dreaming and once I wake up from my dream where I have one hand, I will find myself with two hands.  Moreover, if it seems to me that all of the sudden I only have one hand and I think that I was having a delusion the whole time, I would consider that present state a delusion because I have my whole life experience and immediacy of knowledge as evidence.  The same goes for skeptical arguments, etc.  This type of Moorean shift is common and seems totally appropriate.  For more examples, see Moore’s papers on the topic or consider beliefs that are usually taken as foundational in nature.

With regards to (5), if the belief that I have two hands is of such a nature that I cannot have a fact that will defeat my belief due to its intrinsic defeater-defeater, then that belief is clearly not open to revision.  For if it were open to revision, that means it could be defeated.  Since that is not the case, then (5) holds.

Therefore, (2) follows which means that (3) follows in the main argument.  Empiricism is therefore defeated; that is, if it is open to revision.