in fact, the very diverse and shifting conscious interests of individuals result from the pursuit of this permanent aim in changing conditions. In other words, an indi-vidual’s particular cognitive goal at a given moment is always an instance of a more general goal: maximising the relevance of the information processed. We will show that this is a crucial factor in human interaction. Among the facts made manifest to Mary by Peter’s behaviour is the very fact that he has behaved in a certain way. Suppose now that she pays attention to this behaviour, and comes to the conclusion that it must have been deliberate: per-haps he is leaning back more rigidly than if he were merely trying to find a more comfortable position. She might then ask herself why he is doing it. There may be many possible answers; suppose that the most plausible one she can find is that he is leaning back in order to attract her attention to some particular phenomenon. Then Peter’s behaviour has made it manifest to Mary that he intends to make some particular assumptions manifest to her. We will call such behaviour – behaviour which makes manifest an intention to make something manifest – ostensive behav-iour or simply ostension. Showing someone something is a case of ostension. So too, we will argue, is human intentional communication. The existence of ostension is beyond doubt. What is puzzling is how it works. Any perceptible behaviour makes manifest indefinitely many assumptions. How is the audience of an act of ostension to discover which of them have been inten-tionally made manifest? For instance, how is Mary to discover which of the phe-nomena which have become manifest to her as a result of Peter’s behaviour are the ones he intended her to pay attention to? Information processing involves effort; it will only be undertaken in the expec-tation of some reward. There is thus no point in drawing someone’s attention to a phenomenon unless it will seem relevant enough to him to be worth his attention. By requesting Mary’s attention, Peter suggests that he has reason to think that by paying attention, she will gain some relevant information. He may, of course, be mistaken, or trying to distract her attention from relevant informa-tion elsewhere, as the maker of an assertion may be mistaken or lying; but just as an assertion comes with a tacit guarantee of truth, so ostension comes with a tacit guarantee of relevance. This guarantee of relevance makes it possible for Mary to infer which of the newly manifest assumptions have been intentionally made manifest. Here is how the inference process might go. First, Mary notices Peter’s behaviour and assumes that it is ostensive: i.e. that it is intended to attract her attention to some phe-nomenon. If she has enough confidence in his guarantee of relevance, she will infer that some of the information which his behaviour has made manifest to her is indeed relevant to her. She then pays attention to the area that has become visible to her as a result of his leaning back, and discovers the ice-cream vendor, the stroller, this dreadful William, and so on. Assumptions about William are the only newly manifest assumptions relevant enough to be worth her attention. From this, she can infer that Peter’s intention was precisely to draw her attention to William’s arrival. Any other assumption about his ostensive behaviour is inconsis-tent with her confidence in the guarantee of relevance it carries.

DOI link for in fact, the very diverse and shifting conscious interests of individuals result from the pursuit of this permanent aim in changing conditions. In other words, an indi-vidual’s particular cognitive goal at a given moment is always an instance of a more general goal: maximising the relevance of the information processed. We will show that this is a crucial factor in human interaction. Among the facts made manifest to Mary by Peter’s behaviour is the very fact that he has behaved in a certain way. Suppose now that she pays attention to this behaviour, and comes to the conclusion that it must have been deliberate: per-haps he is leaning back more rigidly than if he were merely trying to find a more comfortable position. She might then ask herself why he is doing it. There may be many possible answers; suppose that the most plausible one she can find is that he is leaning back in order to attract her attention to some particular phenomenon. Then Peter’s behaviour has made it manifest to Mary that he intends to make some particular assumptions manifest to her. We will call such behaviour – behaviour which makes manifest an intention to make something manifest – ostensive behav-iour or simply ostension. Showing someone something is a case of ostension. So too, we will argue, is human intentional communication. The existence of ostension is beyond doubt. What is puzzling is how it works. Any perceptible behaviour makes manifest indefinitely many assumptions. How is the audience of an act of ostension to discover which of them have been inten-tionally made manifest? For instance, how is Mary to discover which of the phe-nomena which have become manifest to her as a result of Peter’s behaviour are the ones he intended her to pay attention to? Information processing involves effort; it will only be undertaken in the expec-tation of some reward. There is thus no point in drawing someone’s attention to a phenomenon unless it will seem relevant enough to him to be worth his attention. By requesting Mary’s attention, Peter suggests that he has reason to think that by paying attention, she will gain some relevant information. He may, of course, be mistaken, or trying to distract her attention from relevant informa-tion elsewhere, as the maker of an assertion may be mistaken or lying; but just as an assertion comes with a tacit guarantee of truth, so ostension comes with a tacit guarantee of relevance. This guarantee of relevance makes it possible for Mary to infer which of the newly manifest assumptions have been intentionally made manifest. Here is how the inference process might go. First, Mary notices Peter’s behaviour and assumes that it is ostensive: i.e. that it is intended to attract her attention to some phe-nomenon. If she has enough confidence in his guarantee of relevance, she will infer that some of the information which his behaviour has made manifest to her is indeed relevant to her. She then pays attention to the area that has become visible to her as a result of his leaning back, and discovers the ice-cream vendor, the stroller, this dreadful William, and so on. Assumptions about William are the only newly manifest assumptions relevant enough to be worth her attention. From this, she can infer that Peter’s intention was precisely to draw her attention to William’s arrival. Any other assumption about his ostensive behaviour is inconsis-tent with her confidence in the guarantee of relevance it carries.

in fact, the very diverse and shifting conscious interests of individuals result from the pursuit of this permanent aim in changing conditions. In other words, an indi-vidual’s particular cognitive goal at a given moment is always an instance of a more general goal: maximising the relevance of the information processed. We will show that this is a crucial factor in human interaction. Among the facts made manifest to Mary by Peter’s behaviour is the very fact that he has behaved in a certain way. Suppose now that she pays attention to this behaviour, and comes to the conclusion that it must have been deliberate: per-haps he is leaning back more rigidly than if he were merely trying to find a more comfortable position. She might then ask herself why he is doing it. There may be many possible answers; suppose that the most plausible one she can find is that he is leaning back in order to attract her attention to some particular phenomenon. Then Peter’s behaviour has made it manifest to Mary that he intends to make some particular assumptions manifest to her. We will call such behaviour – behaviour which makes manifest an intention to make something manifest – ostensive behav-iour or simply ostension. Showing someone something is a case of ostension. So too, we will argue, is human intentional communication. The existence of ostension is beyond doubt. What is puzzling is how it works. Any perceptible behaviour makes manifest indefinitely many assumptions. How is the audience of an act of ostension to discover which of them have been inten-tionally made manifest? For instance, how is Mary to discover which of the phe-nomena which have become manifest to her as a result of Peter’s behaviour are the ones he intended her to pay attention to? Information processing involves effort; it will only be undertaken in the expec-tation of some reward. There is thus no point in drawing someone’s attention to a phenomenon unless it will seem relevant enough to him to be worth his attention. By requesting Mary’s attention, Peter suggests that he has reason to think that by paying attention, she will gain some relevant information. He may, of course, be mistaken, or trying to distract her attention from relevant informa-tion elsewhere, as the maker of an assertion may be mistaken or lying; but just as an assertion comes with a tacit guarantee of truth, so ostension comes with a tacit guarantee of relevance. This guarantee of relevance makes it possible for Mary to infer which of the newly manifest assumptions have been intentionally made manifest. Here is how the inference process might go. First, Mary notices Peter’s behaviour and assumes that it is ostensive: i.e. that it is intended to attract her attention to some phe-nomenon. If she has enough confidence in his guarantee of relevance, she will infer that some of the information which his behaviour has made manifest to her is indeed relevant to her. She then pays attention to the area that has become visible to her as a result of his leaning back, and discovers the ice-cream vendor, the stroller, this dreadful William, and so on. Assumptions about William are the only newly manifest assumptions relevant enough to be worth her attention. From this, she can infer that Peter’s intention was precisely to draw her attention to William’s arrival. Any other assumption about his ostensive behaviour is inconsis-tent with her confidence in the guarantee of relevance it carries.