-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I believe the question is ill-formed. This "directionality" of relationships is an abstraction. And from that perspective, yes, directionality is purely a function of the perspective adopted by the model.
A model of a living system can be uni-directional or bi-directional. But, I believe the living system can't be _fully_ described in those terms. It also seems plausible that a model can be both bi- and uni-directional if the model has multiple scales. But, I don't think we can say with any certainty that the model's referent (the living system) is uni-, bi-, multi-, or non-directional. We can only say things like: "using model X, which is uni-directional, we can predict behavior Y in the system" or "model X has been validated against behavior Y in the system and model X is uni-directional, hence (by parsimony) we posit that behavior Y in the system is the result of a uni-directional mechanism". Note the fulcrum: "behavior Y". Louis Macovsky wrote: >>>So, I again submit that there usually (always?) is bi-directionality > in living systems, but perhaps others will have examples where > mono-directionality (As Robert said: " The cause-and-effect arrow of > implication is one-way.") is the only case.<< > > Isn't "mono vs. bi" directionality dependent upon model "grain" or or > the bias of scale. I would think all one-way causal relationships can > become bidirectional as perspective zooms in or out. > > Bidirectionality can be represented by a causal *loop* diagram where the > cause-and-effect arrow is always one-way. - -- glen e. p. ropella, 971-219-3846, http://tempusdictum.com Everything is vague to a degree you do not realize till you have tried to make it precise. -- Bertrand Russell -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGaCO0ZeB+vOTnLkoRAh/xAJ404RF47RyyxBaCo2RhgfUyG8Y6jACgtvxN ydvFiXFFAiFTNoc6Pdp+x+A= =kBal -----END PGP SIGNATURE----- ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
