True and False Sense-Impressions in Epicureanism and Stoicism.

 

 

My PhD thesis tackles epistemological and metaphysical issues that stem from the Epicurean and Stoic theories of perception, which were in part shaped by the debate against the ancient sceptics. It compares the different ways in which these schools conceptualise and individuate sense-impressions, and explain how–and to what extent–impressions equip us to acquire knowledge about the world in the face of various sceptical challenges.

 

The main body of the thesis is structured in three chapters:

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• Chapter 1

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In the first chapter I analyse Epicurus’ view that all sense-impressions are true, an epistemological position that Epicurus thought to be the only way of avoiding the spectre of scepticism.

 

According to the standard interpretation of Epicurus’ theory of sense-impression, all sense-impressions are true insofar as they infallibly report the nature of their respective immediate causes, i.e. the atomic films (eidōla) given off by ordinary objects and impinging upon the sense-organ. As I contend, however, this reading does not fit well with the Epicurean claim that what is perceived via the eidōla are the ordinary objects themselves. Second, if the objects of sense-impression are not the ordinary objects themselves, but the eidōla, then we have no way to confirm whether those entities do indeed correspond in a robust way with how the ordinary object is. After raising these criticisms, I argue that Epicurus’ position is best understood if we take the senses to report on how ordinary objects appear to us instead of on how they are (an interpretation I call the ‘phenomenal reading’). As I go on to explain, on the one hand, the fact that our senses provide us with information about how ordinary objects appear does not mean that the senses are cut from the external world, for by telling us how ordinary objects appear, the senses report on a real/objective relational or dispositional quality of the object. On the other hand, although perceptual reports do not tell us how things are in themselves or per se (kath’ hauta), they should not be regarded as trivial or uninformative, for it is precisely on the basis of the information provided by the senses that we can make, with the aid of reason, justified inferences that go beyond our own affections and establish how things are independently of how we perceive them.

 

• Chapter 2

 

The second chapter is a study of sense-impression in Stoicism, with an emphasis on the debate between the Stoics and the Academic Sceptics concerning the cognitive impression (phantasia katalēptikē). Given that the Stoics faced several sceptical attacks on different flanks, I address some of these attacks insofar as they challenged and have implications for the Stoic epistemological position, and show how the Stoics adjusted their notion of cognitive impression in view of the Academic objections.

 

According to the Stoics, some impressions are false or deceptive, some are true, and others–namely, the cognitive impressions–are not just true but necessarily so, such as to command assent. On their view, it is only to this last type of true impressions to which the Stoic sage is supposed to give assent: the sage does not opine but assents only to those impressions she knows to be true. One of the lines of criticism adopted by the Academics was to argue that if the Stoic sage is to avoid assenting to non-cognitive impressions, then she must refrain from assenting to any sense-impression, for she cannot be sure that any of the impressions she entertains are true. I conduct a detailed examination of the indistinguishability arguments the Academics put forward to support the view that, given the epistemic strictures imposed on the sage by the Stoics themselves, the sage must have no beliefs and live as a Sceptic.

 

• Chapter 3

 

The aim of this chapter is to draw together themes from chapters one and two in two ways. First, I show that sceptical attacks against both the Epicurean and Stoic notions of sense-impression adopted a similar tactic: they purport to undermine the empiricist views of their dogmatic rivals involves pointing to the problematic character of pairs of impressions.

 

According to some reports, Epicurus makes all sense-impressions true insofar as each of them infallibly reports on its respective proximate cause (i.e. eidōla), not on how the ordinary objects is. On this view, then, the view that all sense-impressions are true comes at the price of opening a gap between sense-impressions and their respective distal causes, i.e. the ordinary objects. As I explain, this charge depends on a certain interpretation of how the Epicureans respond to putative cases of conflicting sense-impressions, i.e. cases in which a pair of impressions seems to ascribe one and the same object with opposite qualities. According to Sextus’ report (M. VII 206-210), the Epicurean says that the sense-impressions (a) ‘the tower appears square (from close up)’ and (b) ‘the tower appears round (from afar)’ do not conflict with each other because, rather than representing one and the same ordinary object (i.e. the tower), they have different perceptual objects (aisthēta): while (a) accurately reports on the square-shaped eidōla impinging on our eyes when we look at the tower from a short distance, (b) accurately reports on the round-shaped (i.e. distorted) eidōla coming from far away.

 

Similarly, in attacking the Stoics the Academics resort to pairs of sense-impressions taken to be indistinguishable. As they argue, when the Stoic sage entertains a sense-impression she cannot determine whether that sense-impression is true or false because, the thought goes, for every true impression it is possible to find a false one which is exactly alike. And since the sage cannot rule out that any of her sense-impression is false (i.e. a false impression indistinguishable from a true one), she should refrain from assenting to any of them, if she is to be infallible.

 

I show how both the Epicureans and Stoics respond to these attacks based on pairs of sense-impressions by distinguishing each of the impressions in the pair from the other. In the case of the Stoics, for example, the strategy relates to some central claims of Stoic metaphysics which they seem also to have used to respond to other Academic arguments (e.g. the Growing Argument).

 

The second aim of this chapter is to compare the Epicurean and Stoic notions of sense-impression and argue that although both schools take the mind to play the active role of transforming the raw data provided by the senses, they differ insofar as they take this cognitive work to happen at different stages. Crucially, for the Epicureans the mind is not involved in the formation of sense-impression, as on this model the mind reflects upon and interprets perceptual reports (i.e. sense-impressions) only once it has received them from the senses. It is once the mind has passively received sense-impressions that the possibility of error arises, for the mind may make mistakes when transforming a-rational (alogoi) sense-impressions (which are always true) into beliefs or judgements: since transforming imagistic perceptual content into propositional terms requires some interpretative work, the mind may end up distorting the information of perceptual reports. For the Stoics, on the other hand, the mind is involved from an early stage in the formation of sense-impressions, for, at least in the case of rational adults, sense-impressions are a species of rational impressions or thoughts. As scholars usually point out, the content of sense-impressions is propositional and thus cognitively penetrated to the extent that that content is conceptual. On this model, then, the information conveyed by sense-impressions is not merely raw sensory data but has been already conceptualised and put in propositional terms by the mind.