Quantum Mechanics and Intentionality

Quantum Mechanics and Intentionality

Godehard Brüntrup

Henry Stapp’s version of a collapse theory is quite different(Stapp 2007). For him quantum reality, the superposition,collapses into classical reality if probed for a specific information(cf. Heisenberg’s Uncertainty Principle). If a question is asked,for example if measured for a specific spin,the system provides specific information in return.From a philosophical perspective the crucial point here is that the measurement process as asking for a specific information may be seen as something implying intentionality. In that the quantum system is being represented as specific informational content, a meaningful question posed to the system can thus also be represented. Now, unless these expressions are mere metaphors and the real process is simply nothing other than a random collapse, there is some intentionality built into nature wherever these collapses occur.It is not ultimately relevant at what level of nature these probing actions happen;maybe they happen all the time even at the lowest level, or possibly they require some higher form of mentality. In any case they require something that goes beyond a classical mechanism: that nature answers a question posed to the system requires that a decision be made as to what the question will be. According to Stapp, in the collapse a big smear of possibilities is being reduced, and this reduction increases knowledge: by becoming more 12determinateandrealizing possibilities,information is represented in the universe, which in turn can be used to realize new possibilities consistent with what already has happened and what is possible by the laws of nature in the future.The representation of information is thus the key idea in Stapp’s theory; for Stapp quantum theory sees the physical world in terms of information. The billiard ball view of classical materialist atomism is replaced by the notion of a holistic and at least partly nonmaterial world consisting of an objective carrier of a growing collection of non-localized bits of information.

Representation of information, however, is a form of aboutness, it implies some form of intentionality.The crucial philosophical question is whether such intentionality requires consciousness or experience. If we follow account (1) (consciousness derived from intentionality) then a vast quantity of intentional acts of representation will happen without consciousness, and only some very complex one will be accompanied by a moment of full phenomenal consciousness. Following Whitehead’s process metaphysics, Stapp sees the world as dynamically related experiential events.But for Whitehead experience does not necessarily imply consciousness,that is to say that all conscious events are experiences but not all experiences are fully conscious. So, Stapp’s view is in principle open to an interpretation in which some form of non-conscious intentionality (Whitehead calls it ‘prehension’) permeates the universe. Another interpretation might be that the representation of information in a collapse occurs only with respect to fully conscious observers. This would be more in line with account(4),where a strong modal tie between intentionality and consciousness is claimed. Where there is intentionality, there is consciousness. It is not crucially important here to decide this question of interpretation here. What is important is that our hypothesis is corroborated: it is via the notion of intentionality that quantum mechanics becomes relevant for the philosophy of mind.

If nature has –even at the quantum level–the capacity to represent mental content and act on the mental content as such, then there is a form of intentionality built into nature. If account (4) above  is  correct,  then  Bohm’s  theory  implies  a  form  of  panpsychism  in  which  some  form  of consciousness  is  ubiquitous  in  nature.  If  account  (1)  is  correct,  then  there  is  some  form  of unconscious  intentionality  even  at  the  very  basic  levels  of  nature.  Fully  developed  consciousness arises  from  the  complex  configuration  of  these  basic  forms  of  consciousness.In  any  case,  that Bohm  places intentionality into  the  heart  of  matter  via  his  theory  of  active  information corroborates the thesis  that  the  concept  of  intentionality links  quantum  mechanics  to  thep hilosophy of mind

This  many-minds  interpretation is a variant  of  the  many-world interpretation and was  first  proposed  by  H.D.  Zeh  (Zeh  1970). Later  David  Albert  and  Barry Loewer developed an influential version of it (Albert, Loewer 1988). Zeh’s original idea was quite straightforward,  and  his  goal  was to  avoid  distinct  worlds in a  decohering  universe  without necessitating collapses  of  the  wave  functions.  His  idea  was  that  there  is  a  psycho-physical parallelism  between  decoherent  physical  states  and  minds.  The  metaphysical  nature  of  this parallelism  can  be  spelled  out  in  different  ways. It  could  be  that  the  minds  supervene  on  the physical states, it could also be the case that –in a more interactionist-dualist fashion –the minds actively  select  the  physical  states  they  correspond  to.  In  any  case  the  theory  postulates  a  vast number of minds. No minds are split, they existed all along, far more than the individual minds of human persons in the common sense world.In this many-minds interpretation it is obvious that decoherence exists only in relation to a mind which represents its environment from a certain point  of  view.  Representation  by  a  mind,  however,  entails  some  form  of  intentionality. Here again  it  is intentionality  that  connects  this  interpretation  of  quantum  mechanics  to  the philosophy of mind. The role consciousness plays in this theory depends –as might be expected by  now –on  how  we  construe  the  relationship  between  intentionality  and  consciousness.  If  we follow  account  (1),  then  the  minds  of  the  many-minds  theory  need  to  be  conscious.  They  do feature  intentional,representational  states,  but  these states might be in  many  cases  not  complex enough  to  be  classified  as conscious because phenomenal consciousness  requires  some  form  of higher-order  meta-representation.  If  we  follow  account  (4),  then  there  is  a  strong  modal  tie between  intentionality  and  consciousness,and in  any  of  the  many  minds that  represents  a decoherent physical  state  there exists  a phenomenal  consciousness  of  some  sort.  In  fact directly following from this, there will be a vast number of conscious minds in the universe, many more than our common sense view takes for granted.