Reductionistic models

For in vitro toxicity studies and assessment of the barrier function, drug transport, cell physiology, and metabolism as well as the development of delivery systems, cell culture models provide powerful systems for scientific research. As the corneal epithelium is the main barrier for ocular penetration, various corneal epithelial cell cultures were established besides the corneal constructs that mimic the whole cornea and serve as reductionist models for the ocular barrier. In general, two types of cell culture models are available primary cell cultures and immortalized, continuous cell lines. 

One significant limitation of such reductionistic models lies in their inability to reveal the dynamic nature of the systems they portray. These models describe artificial conservative states with no revelation of dynamic transactions and alterations of states. Of course the illusion of movement can be graphically fabricated by collectively changing the coordinate frame, but the transactions within the system are still unaltered. While useful information may be derived from such models, it is imperative that their genesis be well known to the drug designer. 

A defined domain of applicability It is realized that (Q)SARs are reductionist models that inevitably have limitations in terms of the types of chemical structures that can be predicted in other words, define the applicability of the model based on the domain. 

Figure 2 The Concept of Reductionist Models of Human Performance.

So under the reductionist model, mental properties, qua mental, do no causal work in bringing about behavior. But because mental properties are either identical with, or at least reducible to, physical properties, their causal efficacy is somewhat restored. Physical properties are causally potent, and mental properties either just are those physical properties, or they are reducible to those physical properties in some fimdamental sense. So mental properties become causally efficacious, in a derivative sense, as well. 

They are reductionistic models, hence particularly suitable for scientific descriptions. They involve approximations that often do not hold in practice. Many facts remain paradoxical because such facts do not fit in the orbital bonding model. 

The dynamic,s underlying EINSTein is patterned after mobile CA rules, and are somewhat reminiscent of Braitenberg s Vehicles [brait84]. Specifically, EINSTein takes a artificial-life-like bottom-up, synthesist approach to the modeling of combat, rather than the more traditional top-down, or reductionist approach,... 

One of the most innovating contributions of the diagnostic model proposed in these guidelines is that it combines idiographic elements within a standardized multiaxial system, in contrast to the conventional, reductionist opinions that favor only one of these elements. 

Another crucial problem for any neurochemical model is cause and effect. Neuroleptics have a high affinity for dopamine receptors, particularly the D2-subtype. There is also a highly significant positive correlation (r > +0.9) between this receptor binding and their clinical potency (Seeman, 1980). But, this does not necessarily implicate elevated dopamine levels as the cause of schizophrenia. Moreover, blockade of dopamine receptors happens very rapidly, whereas clinical benefits are only seen after chronic treatment. Rose (1973) has criticised the reductionist statement that an abnormal biochemistry causes schizophrenia because it relates cause and effect at different organisational levels (namely, the molecular and behavioural). But, while it can be legitimate to discuss cause and effect at the same level that chlorpromazine blocks dopamine receptors (one molecule altering the response of another), it is not valid to infer that increased dopamine activity causes schizophrenia. Put another way ... 

My intention here is not to recall horror tales from the crypt , the extremes to which reductionists may threaten, malign, sensor, and censure scientists pursuing nonreductive alternatives to monophyly. Rather, I will show how polyphylism can flesh out evolutionary skeletons and prepare the way for modeling evolution itself. 

Stan Shostak No, I have much more respect for models than to call them analogies. Models are serious business. You allow a model to work and figure out the parts of the model. It is not a matter of taking the truck apart. You drive your truck up and it suddenly stops. Reductionist - Well, I ran out of gas. Put some gas into the tank, truck starts again, you drive off, you don t care whether that s the real explanation, but it works. Your computer breaks down, you have a crash, you can t put gas in the tank, you reboot. That s the model. Where reductionism doesn t work, you begin with modelling. 

In the period after Murray first produced his models, molecular biology has provided more and more of the proximate why-necessary explanations that the reductionist demands for the historical facts about butterfly eyespots. 

In this essay, I argue for a new perspective on units of evolutionary transition. I analyze the process of reproduction, which leads to a conception of units of evolution as reproducers. These units resolve to more familiar ideas of replicators or interactors at levels of spatial organization when explicit spatial and functional models are imposed on abstract reproducers. I also sketch a heuristically promising program of reductionistic research that flows from the new perspective. 

Another example, and here Claude Debru will probably disagree with me, where co-operative phenomena have been given reductionistic explanation very, very successfully is the allosteric model, where, even though the model is complicated, which is a separate issue, it s purely mechanistic interactions that ultimately do give explanation. 

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