1. Strong and Weak Emergence, by David Chalmers  Weak emergence involves “epistemic emergence.”  On this view, we can deduce, at least in principle, the laws of a higher domain from a lower domain.  On the other hand, strong emergence involves what is called “ontological emergence.”  For strong emergence, we cannot even in principle deduce the phenomena of a higher domain from a lower.  Because weak emergence is epistemic in nature, it involves the concept of the unexpected, and is often invoked by philosophers in discussions of emergence.

2. McLaughlin Essay – Emergence & Supervenience  J S Mill –  Homopathic laws;  Joint effect of several causes identical with sum of separate effects, vector addition; same as sum of parts.  Heteropathic laws;  Chemical products are not mere sum of each reactant. New effect arises from combination of elements; goes over and above sum of parts.

3. Heteropathic means emergent.  Samuel Alexander  Emergent properties must be accepted with “natural piety.”  C D Broad  Argued that emergence involves hierarchy of scientific laws.  Involves notion of irreducibility  Intra-ordinal laws – laws that stay on same level (horizontal).  Trans-ordinal laws -- (vertical between levels); can’t be deduced from lower levels.

4. Illustration of levels:  Social sciences  Psychology  Biology  Chemistry  [Mathematics]  [Logic]

5. Bedau Essay, Is Weak Emergence Just in the Mind?  Main points  Weak emergence is actually part of the structure of the world, not just in the mind  Weak emergence does not violate the causal closure principle.  Weak emergence is consistent with naturalism – no external, non-natural causes

6. Chalmers argument  Strong emergence can be cases of weak emergence, but the converse is not true.  Weak emergence may not involve strong emergence, and just because something is unexpected does not mean it cannot be deduced given sufficient ingenuity and attention.  Chalmers cites cellular automata as a paradigm of weak emergence. High level patterns were unexpected but their formation could be deduced from the rules and initial conditions.

7. Chalmers argues that strong emergence is  More radical than this. It holds that there are some complex systems that cannot be deduced from a knowledge of all the particles in space and time.  If this is true, then it is essentially a rejection of physicalism.  Chalmers believes that strong emergence exists. What phenomena would he consider as a case of strong emergence?  Surprisingly, Chalmers cites the phenomenon of consciousness as evidence of strong emergence.

8. Equally surprisingly  Chalmers believes this is the only case of strong emergence. All the other complex systems in the world are examples of weak emergence.  How does Chalmers demonstrate that consciousness is an example of strong emergence?  He does so by criticizing physicalist explanations of mind and body.  He cites indirect knowledge vs. direct knowledge, zombie cases, and multiple realizability.

9. He argues for  Supervenience of the mental on the physical and suggests that there are lawful correlations between mental states and brain states.  Chalmers discusses the notion of downward causation. This means that a higher level order is not reducible to a lower level, but also exerts causal power on a lower level.  His main example for this involves Quantum Mechanics, whereby the collapse of the wave function is supposedly caused by our conscious observation of it.  He rejects the opposite view of epiphenomenalism where there are strong emergent qualities but where there is no strong downward causation.

10. Chalmers cites what he believes are examples of weak emergence:  The Game of Life  Connectionist networks  Overloaded operating systems  Evolution by natural selection.  He believes that all the emergent properties in these examples are deducible, though with difficulty.

11. It is sometimes said that  Emergence is where the higher order system has properties that are not possessed by the lower order system, i.e., that the whole is greater than the sum of its parts.  Chalmers believes this proves too much. There are too many things that would fit this definition, e.g., file cabinets, a deck of cards, logic gates, etc.

12. It is also claimed that  An emergent system is one that can be deduced but that cannot be reduced to a lower system.  Chalmers rejects this since the notion of reducibility is not always clear.

13. Chalmers concludes his discussion by pointing to epistemic traits that can help us understand weak emergence. Qualities such as  “interesting,”  “difficult,”  “non-obvious,”  “simple,”  Are qualities that capture the notion of weak emergence  Chalmers points out, however, that these are “observer- relative concepts.”

14. Criticisms:  I think a large problem with the distinction between weak and strong emergence is how could you ever tell them apart?  Just because we think we have a case of strong emergence today doesn’t mean it won’t be a case of weak emergence tomorrow as our knowledge of the world increases.  There is no way even in principle of telling these two situations apart.  The notion of novelty and unexpectedness with regard to emergent properties seems false for the simple reason that our analysis doesn’t start with lower levels and work its way up.

15. Rather,  Analysis starts with already existing “higher” systems and works its way down to the components of that system.  It is impossible in principle to be surprised when one is going from the higher to the lower, from the top to the bottom.  Another problem is that Chalmers wants to settle a philosophical problem by appeals to current theories in science, such as QM and the theory of evolution.  However, science changes over time, and both QM and the theory of evolution may change as well.

16. And  Even if they don’t the Copenhagen Interpretation of QM ―upon which Chalmers bases his theory of downward causation of consciousness― is highly controversial.  In short then, the changing nature of science, the theory- saturation of some of its views, and the need for more permanent philosophical explanations, suggest that it is not good judgment to appeal to science to prove a philosophical case.

17. The main concern  I have with Chalmers’ argument is that he uses the nature of consciousness as a proof of strong emergence, when it is the nature of consciousness itself that needs an explanation.  If the nature of consciousness is physicalist, then an appeal to consciousness to support strong emergence would be pointless.  Chalmers would have to demonstrate the incorrectness of the physicalist view of mind, and I don’t really think he has done so.

18. I don’t regard  Appeals to indirect vs. direct knowing, or zombie worlds, or multiple realizations, as sufficient to overcome the presumptive evidence for physicalism with regard to the mind.  And even if physicalism were false, Chalmers would need to provide a positive argument for his view of the mind, not merely a negative case against physicalism, in order to support his view that strong emergence exists.  The fact that he cannot find any more examples of strong emergence other than consciousness suggests that its uniqueness is rather convenient for his argument.

19. One might ask Chalmers that  If all other complex systems are examples of weak emergence, how does he know that consciousness might not also be an example of weak emergence?  Since he has no other proofs of strong emergence, he must resort to a dogmatic presumption that consciousness will never be proven to be a case of weak emergence in the future.  That does not appear to be a very convincing case for strong emergence.  In fact, Chalmers’ discussion provides more reason to believe that consciousness will turn out to be a case of weak emergence― and that is certainly an unexpected result of his argument!

20. Dr. Watson’s Response  Chalmers would not accept that he has provided only a negative argument…  Dualism is a negative conclusion (M is not identical to P) so the argumentation will always involve an attempt to prove a negative (which Chalmers thinks Zombies will provide…  Chalmers would resist the charge of a 'dogmatic' presumption that consciousness will not be given a weak-emergence explanation in the future... he has offered reasons...