Lately since 2012, there has been a theory in development called the
Integrated Information Theory which has huge repercussions: That everything in nature has a certain form of consciousness (consistent with several religious philosophies - See
Panpsychism). In a way, we might be able to measure the "sentience" of beings - from Artificial intelligence to insects to even the human brain.
This theory was the brainchild of neuroscientist Giulio Tononi and what is really interesting about this theory is that it actually has an extremely close relationship with actual studies - in other words, the theory is proving itself to be verifiable and repeatable.
The theory is pretty complex if I were to spell out all the mathematics, but here's a sum of what I gather from the theory after reading the papers and doing some self-research:
(A) If a system CAN be reduced, consciousness does not exist at that level.
For example, if you had a brain - but removed the cerebellum, the visual cortex, etc - somehow, patients have shown that you STILL have consciousness. In other words, the whole brain does not equate to consciousness.
(B) Consciousness is measured by an index, Phi ϕ .
This theory states that the more "unified" the system is, the LESS reducible it is. Hence, this correlates with consciousness. The higher Phi is, the "larger" the most-reducible unit of that system. Hence, the system is more capable of a "higher" consciousness.
You don't have to know what this equation means, but basically it is as I've summed up above: The more information being generated at the level of a defined system, the LESS reducible it is. And the more information relative to OTHER systems, a higher phi will show that more information is generated at the least-reducible level.
(C) IIT is based off 5 axioms as of version 3.0.
1.
Consciousness exists: The experience exists intrinsically and is not affected by external observation, etc.
2.
Consciousness is compositional: It has directions, you can differentiate the different elements within an experience.
3.
Experience is differentiated: Whenever we experience something, we generate a "contrast" from our history.
4.
Experience is unified: Despite having both a left and right eye, we perceive everything as a SINGLE experience - a unified "one".
5.
Consciousness is exclusive: You can take away the sense organs and the brain is still able to generate images from within itself.
(D) IIT is consistent with evolutionary theory.
The current theory is that the more "unified" a system is, the more information can be generated within that level and transferred among its parts. Hence, this "communication" allows for a higher biological fitness (which just means the chance of survival to the point of producing an offspring).
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Pretty interesting theory from what I've gathered. The only question is how far can we move from a consciousness index? We're still skimming the surface - but what we have now is that the "mind" is like a multi-dimensional mathematical structure that doesn't exist directly within the physical plane. Very hopeful for this theory's development, it sounds very promising.
![\Phi (X(mech,x_1)) = H[p(X_0(mech,x_1)) \parallel \Pi p( ^k M_0(mech,\mu_1))]](http://upload.wikimedia.org/math/e/b/9/eb991497dea50ef1045633fa60a1d2ec.png)
