Developments in machine learning and computing power suggest that artificial general intelligence is within reach. This raises the question of artificial consciousness: if a computer were to be functionally equivalent to a human, being able to do all we do, would it experience sights, sounds, and thoughts, as we do when we are conscious? Answering this question in a principled manner can only be done on the basis of a theory of consciousness that is grounded in phenomenology and that states the necessary and sufficient conditions for any system, evolved or engineered, to support subjective experience. Here we employ Integrated Information Theory (IIT), which provides principled tools to determine whether a system is conscious, to what degree, and the content of its experience. We consider pairs of systems constituted of simple Boolean units, one of which -- a basic stored-program computer -- simulates the other with full functional equivalence. By applying the principles of IIT, we demonstrate that (i) two systems can be functionally equivalent without being phenomenally equivalent, and (ii) that this conclusion is not dependent on the simulated system's function. We further demonstrate that, according to IIT, it is possible for a digital computer to simulate our behavior, possibly even by simulating the neurons in our brain, without replicating our experience. This contrasts sharply with computational functionalism, the thesis that performing computations of the right kind is necessary and sufficient for consciousness.

翻译：机器学习与计算能力的发展表明，通用人工智能的实现已近在眼前。这引发了关于人工意识的问题：如果一台计算机在功能上等同于人类，能够完成人类所有行为，它是否也会像我们有意识时那样体验视觉、听觉和思维？要基于原则回答这个问题，必须依托以现象学为基础的意识理论，该理论需阐明任何系统（无论是进化形成还是人工构建）支持主观体验的必要与充分条件。本文采用整合信息理论（IIT），该理论提供了一套原则性工具，用于判定系统是否具有意识、意识程度及其体验内容。我们研究由简单布尔单元构成的两组系统，其中一方——基础存储程序计算机——以完全功能等价的方式模拟另一方。通过应用IIT原理，我们证明：（i）两个系统可实现功能等价而不具备现象等价性；（ii）该结论不依赖于被模拟系统的具体功能。我们进一步证明，根据IIT理论，数字计算机完全可能在模拟人类行为（甚至模拟人脑神经元活动）的同时，并不复现人类的意识体验。这一结论与计算功能主义形成鲜明对比，后者主张执行特定类型的计算是意识的必要且充分条件。