Received: 19 March 2015 Revised: 15 November 2016 Accepted: 16 December 2016 DOI 10.1111/phc3.12409 ARTICLE Thomas Reid on Signs and Language Lewis Powell University at Buffalo, SUNY, USA Abstract Correspondence Lewis Powell, Department of Philosophy, Thomas Reid's philosophy of mind, epistemology, and philosophy of University at Buffalo, SUNY, Buffalo, NY language all rely on his account of signs and signification. On Reid's 14260‐4150, USA. view, some entities play a role of indicating other entities to our Email: [email protected] minds. In some cases, our sensitivity to this indication is learned through experience, whereas in others, the sensitivity is built in to our natural constitutions. Unlike representation, which was pre- sumed to depend on resemblances and necessary connections, sig- nification is the sort of relationship that can occur without any intrinsic ties between the sign and the thing signified. Of particular interest is the priority Reid gives to natural signs (in contrast with artificial signs, that is, those signs instituted by humans). Reid deploys his robust account of natural signs in a way that allows him to sidestep some skeptical worries common in the early modern period, as well as in grounding “artificial” human languages like English or Cantonese on a more basic human capacity for communi- cation, that is, itself, the result of our sensitivity to natural signs of other people's minds. 1 | INTRODUCTION Although philosophical discussion of signs is not at all uncommon among early modern figures, Thomas Reid's account of signs and signification plays a relatively more prominent role in his philosophy than can be said for many of his con- temporaries, especially the views he presents in his Inquiry into the Human Mind on the Principles of Common Sense (IHM, Reid, 2000).1 For our purposes, it will be helpful to think of signs as, roughly, indicators of other things, that is, entities where being aware of them leads (or can lead) you to think about, or believe in, some other entity. Although he also treats signs in connection with language and communication, the decision to deeply integrate signs into his philosophy of mind and epistemology allows Reid to offer an account of the human mind that is able to address the skeptical worries that emerged from works by, for example, Berkeley and Hume and that plague the views of virtually all modern philosophers. Understanding the role signs play in Reid's thinking is crucial for developing a sophisticated understanding of how Reid views the workings of the mind, epistemology, and our capacity for communication. With respect to epistemol- ogy, Reid regards signs as integral to the way we acquire knowledge. With respect to philosophy of mind, Reid's views on signs help to explain how we are able to even possess thoughts about a variety of extra‐mental objects and qual- ities that we would otherwise be unable to conceive of. And with respect to language, Reid views human languages as systems of artificial signs, which means that his views on signs provide us with the framework for understanding his Philosophy Compass. 2017;12:e12409. wileyonlinelibrary.com/journal/phc3 © 2017 The Author(s) 1of10 https://doi.org/10.1111/phc3.12409 Philosophy Compass © 2017 John Wiley & Sons Ltd 2of10 POWELL treatment of speech and communication. Reid divides signs into two major types: natural and artificial. Natural signs are those entities that signify independent of any human conventions, whereas artificial signs all rely on human actions/volitions for their status as signs.2 1.1 | Reid's Divisions of Natural Signs Despite their key role in his work, Reid does not provide us with his own definition of “sign” or “signification”. How- ever, he does provide two necessary conditions on how we can gain knowledge from signs: First, That a real connection between the sign and the thing signified be established, either by the course of nature, or by the will and appointment of men.[…]Another requisite to our knowing things by signs is, that the appearance of the sign to the mind, be followed by the conception and belief of the thing signified. Without this the sign is not understood and interpreted; and is therefore no sign to us, however fit in its own nature for that purpose. IHM 6.21 p. 177 According to Reid, for us to gain knowledge by signs, there has to be a real connection between the sign and the thing signified, and we have to have a sensitivity to the sign that leads us to conceive of/believe in the thing signified. In the next section, we'll examine the nature of that sensitivity more closely, as the details of how we transition from a sign to thoughts of the things signified play an important role in understanding Reid's epistemology. How should we understand this requirement of a real connection? It must be read as a rather weak condition. Reid is clear that signs (whether artificial or natural) do not require similarity with the things they signify nor is any evidence required of a necessary connection between the sign and the thing signified (cf. IHM 5.3 p. 58–59). So we have to understand the connection as one like that between the word “gold” and an idea of gold, which is surely not something like a metaphysically or epistemically necessary connection. The minimal sort of connection required for natural signs is something closer to routine co‐occurrence, rather than anything like causation or an intrinsic relation of resemblance. This feature is important because it illustrates a key difference between signification and representation (at least, as the latter was understood in the early modern period). Although representing was taken to require similarity or like- ness between the representation and the thing represented, signifying had no such restriction. This makes sense, as the category signification includes arbitrary human signs (like the word “gold”, or the system of red, yellow, and green lights used to signal instructions to drivers), which obviously do not require similarity, likeness, or necessary connections. Our focus here is on natural signs, which Reid divides into three types.3 There is no succinct schema for naming these types of natural signs that captures all and only their distinguishing features. I will call the first class “experiential signs”, the second class “instinctual” signs, and the third class “magical” signs. As we will see, the term “instinctual” could apply in some sense to the third class, and despite the fact that Reid himself invokes the term “magic”, one should not take these signs any less seriously than the other two classes: The first class of natural signs comprehends those whose connection to the thing signified is established by nature, but discovered only by experience. IHM 5.3 p. 59–60 Experiential signs would include smoke as a sign of fire or certain clouds as signs of rain. In these cases, the sign is connected to the thing signified in a manner independent of human minds, and we must acquire a sensitivity to the signification through experience of the repeated conjunction of the sign and the thing signified. Reid describes expe- riential signs as comprising the whole of genuine philosophy (including the sciences). The goal of science and philos- ophy is to discover as many of these connections as we can and to determine the most general account of them. A second class is that wherein the connection between the sign and the thing signified, is not only established by nature, but discovered to us by a natural principle, without reasoning or experience. IHM 6.3, p. 59–60 POWELL 3of10 Instinctual signs include things such as facial expressions, tones of voice, and laughter. Reid terms these sorts of signs “the natural language of mankind”, and they play a special role in his treatment of language. The basic idea here is that even an infant is sensitive to the connection between a smile and happiness, a frown and sadness, and the like. Unlike the experiential signs, our sensitivity to these signs is instinctual or innate. Note, however, that the things sig- nified by these natural signs are a category of phenomena that we already have cognitive access to. Seeing a smile can lead me to conceive of happiness, but I was already able to conceive of happiness, having experienced it myself. Reid notes, however, that if we did not have this sensitivity inborn, we would not be able to acquire it. According to Reid, if we did not have an innate sensitivity to these signals of mental activities and emotions, we could not come to discover the connection.4 Although I can already think about happiness, without this innate sensitivity, I would not be in a posi- tion to observe a correlation between your smile and any emotions you are experiencing, because I have no way to observe your emotions so as to notice the correlation.5 A third class of natural signs comprehends those which, though we never before had any notion or conception of the things signified, do suggest it, or conjure it up, as it were, by a natural kind of magic, and at once give us a conception, and create a belief of it. IHM 5.3 p. 59–60 Reid's paradigm cases of magical signs are (a) one's own sensations as signs of an enduring immaterial substance who is the subject of those sensations and (b) sensations of hardness (or other primary qualities) as signs of the quality of hardness (or other primary qualities). The key feature of this class of signs is that the things signified by them are things that we are otherwise unable to conceive of.6 Note the contrast here with instinctual signs: I can't detect Sue's particular joy without her smile and my instinctual transition from seeing the smile to thinking of that joy, but it was not as if joy itself was otherwise beyond my ken.