Are we heading into an era of unending low-level conflict, of foreign interference and buying of influence? In The Weaponisation of Everything, the security expert Mark Galeotti argues that traditional warfare is on the wane, replaced by hybrid wars, disinformation, espionage and subversion. He tells Adam Rutherford that this 21st century way of war often goes unnoticed and can be dangerously destabilising, but it also offers opportunities for those who are able to take full advantage of this new armoury.

The political philosopher Cécile Fabre explores the ethics of espionage and counterintelligence. In Spying Through a Glass Darkly she looks to answer a fundamental question: when is spying justified? In the context of war and foreign policy what actions are morally justified, and when? Fabre brings together philosophical arguments and historical examples to study the moral justification of state blackmail, mass surveillance, treason and bribery.

How far are the subversive techniques discussed uniquely human? It’s a question the primatologist Kirsty Graham considers as she studies the way bonobos and chimpanzees communicate in the field. Her research has shown that both groups share not only the physical form of the gestures but many of the same meanings.

Producer: Katy Hickman