Preferred causality

If integral causality is applied to the energy storage elements as the preferred causality then every storage element in integral causality must have at least one causal path to either an effort sensor De or to a flow sensor (Df). This reachability requirement is a necessary condition. 

If derivative causality is the preferred causality, then all storage elements in integral causality must be able to take derivative causality. If integral causality cannot be turned into derivative causality for some storage elements, then this must be possible after some sensors in appropriate locations have been dualised, i.e. a flow sensor (Df) has been replaced by an effort sensor (De) or vice versa. This requirement is a sufficient condition. 

If derivative causality is assigned to the bond graph as preferred causality, (Fig. 3.1), then both storage elements take derivative causality. The resulting causal conflict at the right-hand 0-junction is resolved by turning the effort sensor into a flow sensor. 

The number q of storage elements that take derivative causality when derivative causality is assigned to a bond graph as preferred causality is termed the bond graph-rank of the state space matrix A and is equal to rank(A) while k equals the number of null modes of A [3]. 

The second condition is also satisfied. The two storage elements can take derivative causality as the preferred causality as indicated in Fig. 3.3. 

There is a preference for a particular causality. For example, in case there is a preference for integration over differentiation with respect to time, the ports of the storage nodes, (M)C and (M)I, may be given a preferred causality, viz., effort-out (C) and flow-out (I), respectively. This will turn out to be the most common preferred causality later, when a causality assignment algorithm is discussed aimed at generating a set of differential equations that is in an optimal form for numerical simulation. 

Continue with (3) until all ports with preferred causality are assigned. If all bonds have obtained their causality after this step a set of ordinary differential equations (ODE) is obtained, if not, the result will be a set of mixed differential and algebraic equations (DAE). 

Straightforward application of the causality assignment to the bond graph in Fig. 1.7 results in Fig. 1.8, where the numbers refer to the sequential order in which the causal strokes were assigned. Note that the two I-type storage elements representing the pendulum point mass do not get their preferred causality. Section 1.5 will explain... 

Elizabeth Lloyd That you cannot give a full explanation of what s happening in the group without giving an account of the gradient, and, in fact, the difference in socioeconomic gradients - I wouldn t prefer to call them causal myself but that they are descriptors of the situation that you cannot take them away from the explanation and understand it in the same way. I said one explains the phenomena in terms of what types of entities and their properties and so I take that to be a standard definition of a reductionist or anti-reductionist position. 

In previous editions of this textbook a number of methods of determining causality have been described and an attempt made to evaluate their relative reliability and validity. It has to be understood that such statistically based methods have, over several dacades, been in competition with common observation and inspired guesswork for the assessment of adverse effects in respect of the need for regulatory action. This is not just a matter of idiosyncratic personal preference but is frequently imposed by the clinical and numerical evidence available. 

Aside from the continuity assumption and the discrete reality discussed above, deterministic models have been used to describe only those processes whose operation is fully understood. This implies a perfect understanding of all direct variables in the process and also, since every process is part of a larger universe, a complete comprehension of how all the other variables of the universe interact with the operation of the particular subprocess under study. Even if one were to find a real-world deterministic process, the number of interrelated variables and the number of unknown parameters are likely to be so large that the complete mathematical analysis would probably be so intractable that one might prefer to use a simpler stochastic representation. A small, simple stochastic model can often be substituted for a large, complex deterministic model since the need for the detailed causal mechanism of the latter is supplanted by the probabilistic variation of the former. In other words, one may deliberately introduce simplifications or errors in the equations to yield an analytically tractable stochastic model from which valid statistical inferences can be made, in principle, on the operation of the complex deterministic process. 

The term irreversibility has two different uses and has been applied to different arrows of time. Although these arrows are not related, they seem to be connected to the intuitive notion of causality. Mostly, the word irreversibility refers to the direction of the time evolution of a system. Irreversibility is also used to describe noninvariance of the changes with respect to the nonlinear time reversal transformation. For changes that generate space-time symmetry transformations, irreversibility implies the impossibility to create a state that evolves backward in time. Therefore, irreversibility is time asymmetry due to a preferred direction of time evolution. 

Boyle s criteria and rules for making his preferred distinctions between matters of fact and causes have the status of conventions. Causal talk is grounded in conventions which Boyle s reports exemplify, just as the construction of the matter of fact is conventional in nature (...). The ultimate justification of convention does not take the form of verbalised rules. Instead the justification of convention is the form of life the total pattern of activities which includes discursive practices. 

Data from animal studies ideally should provide clear evidence of specific reproductive toxicity in the absence of other, systemic, toxic effects. However, if developmental toxicity occurs together with other toxic effects in the dam, the potential influence of the generalized adverse effects should be assessed to the extent possible. The preferred approach is to consider adverse effects in the embryo/foetus first, and then evaluate maternal toxicity, along with any other factors, which are likely to have influenced these effects, as part of the weight of evidence. In general, developmental effects that are observed at maternally toxic doses should not be automatically discounted. Discounting developmental effects that are observed at maternally toxic doses can only be done on a case-by-case basis when a causal relationship is established or refuted. 

An important sub-variety of rational action is strategic behaviour, that is choices that take account of the conjectured or anticipated choices of other agents. The incorporation of the strategic aspect into rational-choice theory allows one to formulate three sets of interdependencies that pervade social life, (i) The reward of each depends on the rewards of all, by envy, altruism or solidarity. (ii) The reward of each depends on the choices of all, by general social causality. (Hi) The choice of each depends on the choices of all, by strategic reasoning. The third objection above can Chen be restated as follows rational-choice theory is not able to take into account that (tv) the preferences of each depend on the actions of all. ... 

In the threC tiered scheme of explanation suggested above, two varieties of causal analysis were involved. First, there are the causal explanations of preferences and other mental states, such as beliefs, emotions etc. I shall refer to this as explanation in terms of sub-intentional causality. Next, there are the causal explanations of aggregate social phenomena as the resultant outcome of many individual actions. This 1 refer to as supra-intentional causality. Metaphorically, the causal mechanisms involved in both cases can be said to operate "behind the back" of the individuals concerned. True, Marx uses that phrase only to refer to supra-intentional causality - the production of unintended consequences that thwart our efforts and subvert our aims. Yet the expression is equally apt as a characterization of the psychic causality that, unbeknown to the agent, shapes his beliefs and desires. Although Marx is best known for his study of supra-intentional causality, one aim of the present work is to argue that he was also a pioneer in the study of preference formation and - especially - belief formation. 

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