T.R. Edward 1 Are there uncontroversial error theories? Author: Terence Rajivan Edward, University of Manchester Abstract. This paper evaluates an argument for the conclusion that in order to produce a viable objection to a particular error theory, the objection must not be applicable to any error theory. The reason given for this conclusion is that error theories about some discourses are uncontroversial. But the examples given of uncontroversial error theories are not good ones, nor do there appear to be other examples available. There are various theories which are classified as error theories. Some of these theories have been subject to much discussion. One example is the theory that any judgement which ascribes a colour property to a material object is false. Another example is the theory that any judgement which asserts or implies that there are objective moral standards is false. These theories have their supporters and their opponents. The purpose of this paper is not to discuss any particular error theory, however. Rather its purpose is to evaluate an argument that it makes sense to describe as meta-philosophical, because the argument concerns how philosophical work on error theories should be pursued. The argument is concerned, more specifically, with what a philosopher who is assessing a particular error theory should not do. Its conclusion is that the philosopher should not produce an objection which can be applied to any error theory. My aim below is to show that the argument that has been made for this conclusion does not succeed. The argument to be considered comes from a paper entitled 'In defence of error theory'. The authors of this paper, David Liggins and Chris Daly, seem to regard T.R. Edward 2 the argument as patently sound, since they do not consider any objections to it. Here is their articulation of it: The following constraint holds on viable objections to error theory. Philosophers need to take care that their chosen objection to a given error theory does not prove too much by yielding a more general objection that applies to any error theory. This is because error theories about certain discourses are compelling: we should be error theorists about, for example, astrology, palmistry and numerology. This places an important constraint on objections to error theory. An objection to a philosophically controversial error theory should not provide an objection to a philosophically uncontroversial error theory. (2010: 211, their emphasis) Liggins and Daly accept the following premise: if there are philosophically uncontroversial error theories, then one should not make an objection to a philosophically controversial error theory that applies to any error theory. They also accept the premise that there are philosophically uncontroversial error theories. From these two premises, they derive their conclusion: one should not make an objection to a philosophically controversial error theory that applies to any error theory. If Liggins and Daly's argument is sound, it seems that any philosopher writing about a particular error theory or about error theories in general ought to be aware of it. This impression fits with how they present their argument. According to them, error theories are rated poorly by a number of philosophers (2010: 210). Their paper seeks to dispute the reasons given for this rating of them. However, the reasons they consider in detail are always reasons for rating a subset of error theories poorly, not any error theory whatsoever. They present the argument above before considering T.R. Edward 3 these reasons, in a section entitled 'How not to object to error theories'. What they convey is that an objection which violates their constraint goes wrong in an elementary way. Nevertheless, they do find two philosophers guilty of producing such objections, namely Hilary Putnam and Susan Hurley (2010: 211-212). Since their argument, if sound, identifies an important constraint and since some philosophers have been charged with violating the constraint, it seems that any philosopher who writes on error theory ought to be familiar with the argument, on the condition that it is sound. But is the argument sound? Below I shall contest their premise that there are philosophically uncontroversial error theories. Liggins and Daly provide us with three examples of discourses which it is uncontroversial to regard as consisting of erroneous claims: astrology, palmistry and numerology. But they do not say why we should be error theorists about these discourses. It is natural to interpret anyone who gives these three discourses as examples, without saying where the error in them lies, as believing that the knowledge that science has provided us with conflicts with the understanding of reality that these discourses involve. If Liggins and Daly are opposed to this interpretation, presumably they would have said so. But to accept that we have the relevant scientific knowledge, one must suppose that radical forms of scepticism are false. Radical forms of scepticism, on the understanding employed here, are sceptical doctrines that deny us knowledge of the external world. For instance, there is the doctrine that one has no external world knowledge because one cannot rule out the hypothesis that one's whole life has been a dream (Hanna 1992: 382-383). If this form of scepticism is true, then we cannot be confident that astrology, palmistry and numerology consist of erroneous claims. Unless one can rule out the dream-life hypothesis, one is not in a position to know how these discourses stand in relation to T.R. Edward 4 the external world. But Liggins and Daly do not attempt to rule out this hypothesis, nor do they dispute the purported consequence of not being able to rule it out. Instead they assume the falsehood of radical forms of scepticism. Much philosophical work assumes that radical forms of scepticism are false. Perhaps we are entitled to argue on the basis of this assumption in most contexts. Philosophy would lose much of its value, one might think, if philosophers with proposals that are opposed to scepticism should always refute the sceptic. Surely then, there is nothing of interest in the observation that Liggins and Daly assume the falsity of radical scepticism. This is an understandable response. However, they are not entitled to the assumption in the context in which they are working. Radical forms of scepticism are error theories as well. We will come to the issue of when a theory counts as an error theory later. For now, we need only observe that these forms of scepticism conclude that each claim which attributes external world knowledge to us is false. Not only are these forms of scepticism error theories; on any plausible explanation of what it is to be philosophically controversial, they are also philosophically controversial ones. (Any appropriate object of philosophical debate is philosophically controversial.) Thus in arguing for a requirement on how we should evaluate philosophically controversial error theories, Liggins and Daly are already assuming that some of the theories to be evaluated are false. Given what they are arguing for, they are not entitled to the assumption. One should not offer an argument for a constraint on how we should evaluate theories of type X which already assumes that one theory of type X is false. Since the premise that there are uncontroversial error theories is not somehow self-evident and since it has been supported in a way that depends on such an assumption, the premise has not yet been justified. T.R. Edward 5 For grasping the problem which has been identified, it is useful to imagine that we are about to evaluate a radical form of scepticism, with the aim of determining whether it is true. Since the object of evaluation is a philosophically controversial error theory, it is important for us to first be aware of what we should and should not do when evaluating a theory of this type, plus the arguments for these constraints. Thus if it is the case that one should not produce an objection that can be applied to any error theory, it is important that we are aware of this constraint and the argument for it. But we can only accept the argument provided by Liggins and Daly by already assuming that the theory we are about to evaluate is false, before we have even begun evaluating. Note that this assumption does not cast the commonsense view that we have external world knowledge as the default position: something that we should regard as true in the absence of overriding considerations. If that was what it did, then we could evaluate the arguments of the radical sceptic to see whether they provide us with a compelling reason for abandoning this position. But Liggins and Daly aim to establish a constraint, not a mere guideline, that is to say, something by which we must always abide. They are therefore leaving no space for the possibility that radical forms of scepticism are true. My response to Liggins and Daly relies on the claim that radical forms of scepticism are error theories. But so far no criterion has been introduced in order to determine what is and is not an error theory. Liggins and Daly open their paper with the following assertion: 'To be an error theorist of a discourse is to claim that none of its sentences are true.' (2010: 209) They later say that this definition is a simplification (2010: 209). The complication that they then introduce is one which they ignore, for the sake of simplicity (2010: 210). It will not be introduced here, because we too do not need to concern ourselves with it. The question is whether T.R. Edward 6 Liggins and Daly must treat radical forms of scepticism as error theories. They write as if each error theory targets a discourse, but they do not define what they mean by 'discourse'. Nevertheless, from their writing, our knowledge claims about the external world would constitute a discourse for them. Discourses are not limited to what we can loosely refer to as disciplines, such as astrology, astronomy and physics. Liggins and Daly also write of moral discourse (2010: 209) and colour discourse (2010: 214). The former consists of sentences which ascribe moral properties to the world, while the latter consists of sentences which ascribe colour properties to the world. (If we define these discourses by the sentences that the relevant error theorists target, both characterizations seem too broad. Moral error theorists typically do not object to sentences ascribing moral permissibility to actions, while colour error theorists typically do not object to the ascription of colour properties to 'inner items', such as mental images.) Radical forms of scepticism also target sentences each of which ascribes a type of property to something. These forms of scepticism target sentences which ascribe the property of having external-world knowledge to persons. There is no reason then for Liggins and Daly to deny that radical forms of scepticism are error theories about a discourse. Although radical forms of scepticism are error theories, there is a temptation to overlook them. The temptation arises because the sceptic about a particular set of beliefs does not say that those beliefs are false, rather that we do not know whether they are true or false. Consequently, the sceptic does not appear to be an error theorist at all. But this appearance is misleading. Since the radical sceptic is a sceptic about our external world beliefs, they do not say that we are in error about the external world. But they do say that we are in error if we ever claim to know about how the external world is. Every claim that attributes external world knowledge to us is T.R. Edward 7 erroneous, according to this kind of sceptic. Thus it is not our external world discourse which this sceptic targets, as an error theorist, rather our discourse of external world knowledge. Liggins and Daly refer to astrology, palmistry and numerology to make their argument. Can the argument be rescued by replacing reference to these things with other examples? If the objection I am making was that there are true sentences from these discourses or that these discourses are too vague to be scientifically tested (Popper 1972: 37), then it would be promising to pursue this defence. But the objection above is quite different. It begins with the inference that Liggins and Daly are relying on our supposed external world knowledge to justify error theories about astrology, palmistry and numerology. If the replacement examples are also discourses that we should be error theorists about because of what we know about the external world, then their argument will be open to the same objection. The replacement that they need is a discourse that we can reject without assuming such knowledge to justify the rejection. An error theory about it must also be philosophically uncontroversial. But it is doubtful that there is any discourse which meets these criteria. Note that an attempt to dispel this doubt must not just uncover a discourse consisting of sentences that are clearly not true. There must also be no philosophical reasons to regard these sentences as meaningless, instead of false, otherwise it will still be controversial to be an error theorist about this discourse (Magidor 2010: 554555). One might wonder whether it is possible to define a particular discourse so that, because of the definition itself, an error theory about this discourse is uncontroversial. For instance, we could say that the discourse of falsehood is a discourse consisting of all false sentences, without specifying which sentences are T.R. Edward 8 false. We could then say that an error theory about this discourse is uncontroversial. But it is not clear that what is being called the discourse of falsehood is genuinely a discourse. Intuitively, the sentences of a discourse have a common subject matter, which is reflected in the label for that discourse. But we have not been told of any common subject matter running through the discourse of falsehood. It may be said that we should not take the word 'discourse' too seriously. But if we allow for error theories that are uncontroversial by definition, there is another point to be made against this attempted defence of the argument. When Liggins and Daly write of an important constraint on objections to error theory, they are intending to present a requirement that cannot be met merely by meeting the general requirement to be consistent. But if there are error theories that are uncontroversial by definition, then any consistent objection to a particular error theory cannot be applied to all error theories. For if an objection also applies to an error theory of this kind, then when we think through the consequences of the objection, we will find that we cannot endorse it without lapsing into inconsistency. Endorsing it would require rejecting an error theory that we ought to accept because of the very way in which the target discourse is defined. Furthermore, if the only philosophically uncontroversial error theories are uncontroversial by definition, then any consistent objection will allow for all of them. A defence of Liggins and Daly's argument which seeks out error theories that are uncontroversial by definition may therefore preserve the letter of the argument, but it will have done so without identifying a requirement that goes beyond the general requirement to be consistent. A defence of the argument that preserves its spirit needs to identify a requirement that is distinct in practice. I cannot see how this can be achieved. T.R. Edward 9 References Daly, C. and Liggins, D. 2010. In defence of error theory. Philosophical Studies 149: 209-230. Hanna, R. 1992. Descartes and Dream Scepticism Revisited. Journal of the History of Philosophy 30: 377-398. Magidor, O. 2010. Category mistakes are meaningful. Linguistics and Philosophy 32, 553-581. Popper, K. 1972 (fourth ed.). Conjectures and Refutations: The Growth of Scientific Knowledge. London: Routledge and Kegan Paul.