A Treatise of Human Nature taste to be in the other), arguing that unextended perceptions must somehow exist without having a location. But the contrary problem arises for dualists: how can extended perceptions (of extended objects) possibly be conjoined to a simple substance? Indeed, Hume waggishly adds, this is basically the same problem that theologians commonly press against Spinoza's naturalistic metaphysics: thus if the theologians manage to solve the problem of extended perceptions belonging to a simple substance, then they give "that famous atheist" Spinoza a solution to the problem of extended objects as modes of a simple substance. Finally, Hume examines "causal relations", arguing
Mixed criticality are composed of a mixture of safety-critical and non-critical parts, as for example when an aircraft contains a passenger entertainment system that is isolated from the safety-critical flight systems. Some issues to address in mixed criticality systems include real-time behaviour, memory isolation, data and control coupling. Computer scientists have developed techniques for handling systems which thus have mixed criticality, but there are many challenges remaining especially for multi-core hardware. Basically, most errors are currently committed when making confusion between priority attribution and criticality management. As priority defines an order between different tasks or messages to be transmitted inside a system,