什么是意识？
意识，指的是经验、感知、感觉，是你睡觉而无梦或昏迷时失去的而醒来时又得到的东西，是我们的内在世界。
本人对理解意识很感兴趣，正在学习如下理论，希望建立一个讨论班一起学习：
整合信息理论 IIT Integrated Information Theory
最近二三十年，神经科学家 Giulio Tononi 与一些人合作提出了这个理论，该理论仍在不断发展中。我个人非常喜欢这样的公理化的研究方式。
首先，通过内省，列出意识具有的六条基本属性：
Existence (0th axiom): Experience exists: there is something.
Intrinsicality: Experience is intrinsic: it exists for itself.
Information: Experience is specific: it is this one.
Integration: Experience is unitary: it is a whole, irreducible to separate experiences.
Exclusion: Experience is definite: it is this whole.
Composition: Experience is structured: it is composed of distinctions and the relations that bind them together, yielding a phenomenal structure that feels the way it feels.
接下来，根据这六条公理，假设其物理基底应该具有的属性：
Existence (0th postulate): The substrate of consciousness can be characterized operationally by cause–effect power: its units must take and make a difference.
Intrinsicality: Its cause–effect power must be intrinsic: it must take and make a difference within itself.
Information: Its cause–effect power must be specific: it must be in this state and select this cause–effect state.
Integration: Its cause–effect power must be unitary: it must specify its cause–effect state as a whole set of units, irreducible to separate subsets.
Exclusion: Its cause–effect power must be definite: it must specify its cause–effect state as this whole set of units.
Composition: Its cause–effect power must be structured: subsets of units must specify cause–effects over subsets of units (distinctions) that can overlap with one another (relations), yielding a cause–effect structure that is the way it is.
最后，用一个数学对象——Phi structure 刻画其物理基底的因果结构。该理论认为，意识的内容与Phi structure 是一一对应的，而意识的有无则相应于Phi structure的某个数字指标是否为零。
