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To this reader, it was Dworkin's meditations on the jurisprudence of death and dying that was so worthy of, at the very least, "cherry-picking" for the poetic insights that go beyond law and ethics to wider, almost spiritual significance. Maybe, thereby, there was the possibility to try and better understand the intellectual project in question-namely, always to defend a kind and inclusive liberality, a true liberalism, more in the English sense than the American. (Dworkin's political mission appears to have been anything but laissez faire and seemed social democratic, which would earn the label " |
In his 1993 book, Death's Dominion, Dworkin gives a timely reminder of the need for tolerance and humanity to permeate all ethical deliberations about the beginning and end of life, be they theoretical or clinical. The way we approach our deaths and those of our fellow human beings is an important ingredient in individual and collective constructs of human dignity: But if people retain the self-consciousness and self-respect that is the greatest achievement of our species, they will let neither science nor nature simply take its course, but will struggle to express, in the laws they make as citizens and the choice they make as people, the |
Power-plant design should prepare for carbon capture SIR -Your News Feature "China's burning ambition" (Nature 435, 1152-1154; 2005) identifies gasification-based technologies as important for limiting future pollutant and CO 2 emissions from China, but it fails to consider another major requirement for any future large-scale reduction strategy. There was no mention of CO 2 capture and storage from the hundreds of new coal-combustion power plants that will inevitably be built in China during the coming decades. These modern power stations are likely to continue in use for about 50 years, and their combined |
Criticism that science is being used as a cloak to hide the purpose of killing whales is inappropriate. The lethal method used for sampling is required to achieve our research objectives, including determination of age and detailed data on stomach contents. Also, parts of Japan's research programme use non-lethal techniques for sighting surveys and oceanographic studies, as well as biopsy sampling. Contrary to the authors' comment that the publication record of our 18-year research programme is "very poor", we have made more than 150 scientific papers available to the SC and had a further 79 published in academic peer-reviewed journals. Unfortunately, many journals reject papers |
Although most discussions of natural kinds in evolutionary biology and systematics focus on metaphysical issues (e.g., what is a natural kind, or which biological things are kinds), epistemological considerations are at least as important (e.g., what epistemic-theoretical aims are pursued by using various natural kinds concepts, or how well are they met using a certain way of grouping objects into a kind). In the case of biological taxa, most biologists and philosophers favor the idea that species are individuals rather than natural kinds. Yet recently some philosophers have interpreted species as natural kinds using a revised notion of 'natural kind' as homeostatic |
While species had originally been considered as classes or natural kinds, the view that species are individuals (SAI) was proposed in response to the serious problems facing a construal of species as kinds (Ghiselin 1974; Hull 1978). Most importantly, species are historical entities: a species originates, it persists across time at specific spatial locations, it can undergo substantial evolutionary change, and it can go extinct. The traditional notion of a natural kind is inadequate when applied to species as this notion was tied to kinds as found in physics and chemistry. The traditional account (used especially by metaphysicians and philosophers of language |
4 nature (e.g., all oxygen atoms share physical properties and can undergo the same chemical reactions). (2) The identity and boundary of a natural kind is metaphysically determined by an essence; an object belongs to the kind in virtue of having this essential property. The essence is epistemologically fundamental in that it explains the characteristic properties of the kind (e.g., the essence of oxygen is its atomic structure, which explains all physical and chemical properties of oxygen). The first condition does not apply to species as there is substantial variation across the members of a species, and even a feature shared by all conspecifics at a time |
Yet the view that species and higher taxa are natural kinds has been revived (Boyd 1999; Griffiths 1999; Keller et al. 2003; Rieppel 2005b Rieppel, 2006 Rieppel, 2007 Wilson 1999 Wilson, 2005, using the view of natural kinds as homeostatic property clusters (HPC) proposed by Boyd (1991). This new philosophical notion of a natural kind was developed so as to do justice to natural kinds as they are studied in biology and other special sciences. It attempts to reconcile the |
are characteristic of the kind, which is necessary for taxa to count as natural kinds. (2) These correlation of properties is brought about and maintained by causal processes (dubbed 'homeostatic mechanisms') in which the kind members figure. It is this set of homeostatic mechanisms that determines the identity of an HPC natural kind, i.e. specifies which objects are kind members, where vague boundaries are permitted. The kind is a 'natural' kind (rather than a nominal kind consisting of objects that are grouped together by mere human convention), as our grouping of entities into an HPC kind is rooted in objective features of nature |
Furthermore, in contrast to the tacit assumption (fitting chemical kinds) that an essence is an intrinsic property, the HPC view explicitly permits extrinsic / relational properties as part of the homeostatic mechanisms characterizing a natural kind. (For a more detailed philosophical account of the HPC construal of natural kinds see Wilson et al., in press.) To illustrate this account briefly with examples, in the case of a higher taxon as a natural kind, the property cluster consists in character distributions, usually phenotypic (and genotypic) features shared by most species belonging to this taxon, i.e. synap |
In the case of a species as a natural kind, the property cluster consists in shared phenotypic and genotypic features or a particular range of variation that several characters exhibit, which make the species a genetically and morphologically cohesive entity. The homeostatic mechanisms accounting for this are those described by some of the species concepts: gene flow and interbreeding, common descent, or ecological selection, all of which are relational properties and not just intrinsic to an organism that is a member of the species. For many species taxa several of these causal processes are relevant for maintaining the species's coherence, so that the identity of a species as |
Note that while the alternative SAI view does not explicitly invoke 'essences' (or homeostatic mechanisms), it is committed to there being some determining features that settle what makes some organisms (but not others) parts of a species and that determine the identity of this species-individual across time. These determining features may be unknown, though they are at least partially laid out by species definitions (Rieppel 2005b). Still, the position that species are individuals has to rely on features determining the identity of a species, viewing these features as specifying which organisms are parts of the species-individual, while a natural |
This provides a relevant motivation for SAI, but has to be qualified. Barker and Wilson (unpubl.) make the useful distinction between integrative and response cohesion. An entity has integrative cohesion if its parts are spatially contiguous and there are strong causal connections between the parts so as to facilitate integration into a whole. A species taxon has only low integrative cohesion: the organisms belonging to a species can occupy remote locations and the causal interaction between conspecifics (interaction within the species-individual) is often no higher than interaction between such parts of the species-individual and other organisms and inanimate objects. In this respect |
"whatever is 'homeostatic' cannot, by definition, evolve" (p. 234). This is first a misconstrual of the HPC view, in that it takes the label 'homeostatic' too literally. 'Homeostatic mechanism' is a technical term that does not imply that the properties of a kind do not change or exhibit variation, rather, it refers to those causal processes that determine the boundary and integrity of the kind. A related objection against the HPC account was brought forward by Ereshefsky and Matthen (2005), who claim that as every natural kind account focuses |
Apart from the issue as to which metaphysical category taxa belong to, an important virtue of some discussions developing the HPC view has been to address epistemological issues in biology. While it is not committed to natural kinds being governed by genuine laws, the HPC view stems from the idea that any adequate scientific account of a particular natural kind permits important inferences (induction) and explanations (Boyd 1991; Griffiths 1999). Boyd (1999) offers a particularly explicit discussion based on the notion of 'accommodation'. The starting point is that biologists have various epistemic aims (inductive |
Several epistemic aims may attach to one and the same natural kind, and a beneficial feature inductions. In addition to this, some of the features shared by members of the kind are more basic in that they form the causal basis for the correlation of the other features. These features making up the homeostatic mechanisms support explanations. For instance, a species shares many properties, to which species concepts focusing on diagnostic and operational properties may appeal (e.g. the morphological species concept, the phenetic species concept, the apomorphy species concept); and a species has a unique evolutionary fate (as pointed out by the evolutionary species |
The HPC approach views these different descriptive and explanatory interests (epistemic aims) as compatible. While one scientific account (e.g. one species concept) represents only some properties of a kind (because those are sufficient to accommodate the specific epistemic interests of a group of biologists), the HPC view highlights how many more properties tied to a kind are metaphysically related. By for instance laying out the causal relations among shared phenotypic features, cohesion mechanisms, evolutionary unity, the HPC approach also provides These are individual organisms in the case of taxa-fundamental biological units to which descriptions and explanations apply. While |
conventional. An individual likewise has a non-arbitrary boundary and distinctive unity across Although metaphysically both approaches are fully compatible, there may be pragmatic reasons to favor one over the other in a certain epistemic context. In evolutionary contexts where species (and sometimes higher taxa) are viewed as evolutionary units that originate, undergo change, and go extinct, they are best viewed as individuals. As explained above, natural kinds can be conceptualized as changing, yet translating from individual talk to kind talk results in a less natural way of speaking in these contexts. In taxonomic contexts, where species and higher taxa are viewed as taxonomic units |
Discussions about biological kinds have focused on species and other taxa. However, the aim of this paper is to arrive at a broader perspective on natural kinds in biology, so that it is vital to together as homologues or structures of the same type (homologies across species). This taxonomic aspect of homology (stressed by taxic approaches to homology) clearly fits the conception that homologues are kinds, just like higher taxa are naturally seen as kinds grouping species according to their phyletically based similarities. Furthermore, a homologue as a part of the body has a morphological and developmental influence (Mü |
kinds-in fact, the question is which possible parts of a body are natural units in that they have a distinct developmental role and can function as independent taxonomic characters. Previous discussions and explicit defenses of the idea that homologues are natural kinds were given by Wagner (1996 Wagner (, 2001 ) and Rieppel (2005a) However, while token homologues are often similar (of the same state) in closely related species, structures in unrelated species can be the same character even if they are in very different character states. How to reconcile this with the idea that a natural kind is defined by |
Which developmental-morphological properties of a structure determine its identity as a homologue and which do not (and thus can vary across species) has to be teased apart by detailed comparative developmental studies. For instance, Wagner (1989) suggested that homologues are characterized by shared developmental constraints. Whatever developmental features are shared by structures when they are governed by the same 'developmental constraints', Wagner was clear about the fact that the sharing of such constraints is consistent with a homologue developing differently in different species (Wagner and Misof 1993), so that while some developmental features are shared by homologues, others are |
Section 1 highlighted the idea that the identity of an HPC natural kind is not necessarily constituted by intrinsic properties, i.e., the homeostatic mechanisms specifying what the kind's members are can include extrinsic or relational properties. This is relevant in the present context because given that a homologue can take on various character states and thereby vary in its internal structure across species, the identity of a homologue may not be determined solely by features internal to this structure. My suggestion is that a structure is a homologue as a unit of phenotypic evolution to the extent that it is distinct from other such units, i.e., to |
In sum, different instances of a homologue in different species may share a host of internal structural properties, which is important for systematics. Yet despite the focus on shared features in many discussions of natural kinds, different instances of a homologue may differ in their character states. The 'homeostatic mechanisms' determining the identity of a homologue as a natural kind are shared by all instances of a homologue, yet these defining developmental features are much lower in number than the many similarities of homologous structures in closely related species and furthermore may include relational properties. This specifies why the structure is a 'natural' kind as a natural |
This developmentally based potential for evolution manifests itself in certain phylogenetic patterns, i.e., distributions of character states. Phylogenetic (taxic) approaches to homology simply focus on the phylogenetic manifestation of the potential for evolution in a character-by- Thus, taxic approaches focus on a homologue as a natural kind in that there is a large cluster of shared character states (at least among closely related species); while developmental approaches focus on a homologue as a natural kind in that there are features that determine the identity of this character as a natural unit of evolutionary change independent of other such units. While pursuing quite distinct |
Apart from kinds defined in terms of structure and/or phylogeny, there are kinds defined in terms of function features, so that an account sensitive to the different kinds of biological kinds has to consider functionally defined kinds such as analogues and ecological kinds. Some philosophers assume that a functional kind is not a natural kind (and instead a set of several natural kinds), on the grounds that a function can be realized by different structural means, so that a functional kind is structurally heterogeneous, in contrast to the traditional vision that a natural kind is defined by a unifying structural feature. However, I argue that a more nuanced picture is needed |
Analogues, in contrast, share significantly less properties than homologues because they are defined in terms of some function. Functional kinds are what philosophers call multiply realizable: there are many different possible physical systems (realizers) that perform the function. E.g., money is a functionally defined category from economics; and it can be realized by such different physical systems as metal (using gold as a currency), paper (bills), electrical states (electronic accounts and transactions)-which have hardly any material properties in common apart from the ones any physical entity possesses. In the case of functionally defined kinds in biology such as analog |
To account for how a particular wing permits flight, the laws of physics have to be applied in a concrete model. 6 But different models are needed to understand different kinds of wings. For instance, modeling insect wing uplift involves non-linear effects resulting from the wing rapidly changing its orientation towards the direction of relative air movement, and the fact that insect wings are not rigid airfoils but change their three-dimensional shape during flight-both factors do not apply for aircraft wings. In sum, while homologues share a host of properties beyond those used in the definition (common ancestry), analogues that are multiply realizable like other functionally |
However, while the members of a kind defined in terms of phylogeny and/or structure (such as homologues) may share more properties than members of a kind defined in terms of function (such as analogues), functional kinds are nonetheless scientifically relevant and figure in certain generalizations. In line with my above remark, Griffiths (1999) acknowledges that there are indefinitely many ways to construct instances of money (so that different instances hardly share any internal structure), yet he points out that the concept of money is a central theoretical notion of economics and figures in generalizations of this field. E.g., there are principles as to |
The HPC account maintains that a natural kind is characterized by a cluster of correlated properties, and that the metaphysical identity of the kind is determined by a set of homeostatic mechanisms, which form the causal basis for the correlation of the former properties. An HPC kind is a natural kind differing from an arbitrary grouping of objects by a merely conventional definition, as there are many more properties shared by most members of an HPC kind than the homeostatic mechanism used to define the kind. The existing correlation of properties can be used for the purposes of scientific induction, and the presence of causal features among them (e.g. home |
are different homeostatic mechanisms specifying the identity of the kind. A higher taxon is defined by common ancestry, and possibly also by the operation of developmental constraints specific to that taxon, which together with common ancestry account for the character similarities among taxon members. A species can be characterized by various cohesion mechanisms (accounting for its unity in evolution), including common ancestry, gene flow, ecological selection, and developmental mechanisms (accounting for phenotypic unity, lifehistories, or stable polymorphisms). This shows that for many natural kinds in biology, its boundary is not defined by a single feature, but by a whole |
For instance, Boyd (1999) and Griffiths (1999) argue that social kinds and other kinds used in the special sciences can be natural kinds, and their examples make this point not by counting how many properties are correlated in such a kind or by assessing to which extent the generalizations they figure in count as laws, but by pointing out that the kinds support explanations that happen to be theoretically important given the scientific aims of the particular fields. Similarly, I acknowledged in the previous section that the individuation of structures in terms of analogy or function is legitimate as it meets some theoretical demands in biology, so that functional kinds can qualify |
In my view, the question as to whether or not a scientific kind is theoretically important cannot be conducted in terms of whether it is a natural kind or another kind. Rather than attempting to offer a unique metaphysical account of 'natural' kind, the more fruitful approach consists in the epistemological study of how and with which success different natural kind concepts (and other concepts) are employed in scientific reasoning. Rieppel (2005b Rieppel (, 2006 Rieppel (, 2007 discusses how theoretical considerations are relevant for how taxonomic terms (conceived as natural kind terms) are |
Some kind concepts support mere descriptions (induction, inference, generalization), other concepts support causal-mechanistic explanations. Some species concepts serve only taxonomic descriptions and classifications, other species concepts support evolutionary explanations. Some meet several such biological demands once combined with other concepts or items of knowledge. To cite just one among several examples, the biological species concept accounts for phenotypic unity within a species (given that the phenotypic expression of genes shared due to gene flow is taken into account), it accounts for some cases of speciation (once biogeographical considerations are added), and it explains how a species can undergo evolutionary change. |
While a kind concept abstracts away from many features of reality and is not able to serve all scientific purposes, the concept may very well succeed in meeting some epistemic aims, so that it is important to get clear about which theoretical-epistemic purposes a natural kind concept is meant to serve (Love, this issue). In some cases, different such epistemic aims are compatible and can be jointly met by an integrated model or account of the kind, and the HPC view of kinds contributes to this by pointing out that many properties can be tied to a single biological kind and exhibit complex relations. Even if the features used |
Can there be free agency, a capacity exemplified by humans as well as by many nonhuman animals, if the world is indeterministic? This question is arguably more important than its mirror image, the question whether free agency is compatible with determinism. But unlike that latter question, the compatibility of free agency and indeterminism is not often addressed explicitly. In this paper we argue that free agency and indeterminism are compatible. We make our case by providing an explicit model in which an indeterministic, stochastic process -a random walk -is constitutive of the behavior and development of a free agent over the course of time |
To begin with the metaphysical side, by determinism we mean the metaphysical claim about our world that as of now, there is only one real possibility for the future to turn out. Indeterminism, on the other hand, is defined simply as the negation of determinism: as of now, there is more than one really possible way for the future to turn out. These definitions refer to the notion of real possibilities for the future, without specifying that notion any further. 2 In the literature, the future possibilities in question are often further specified to be possibilities that are allowed for by the laws of nature given the present |
Turning to action theory, we will use the expression 'free agency' and related terms in the following way: Free agency is a capacity of certain beings, free agents. These agents act freely at least some of the time. We contrast a free action with non-agentive, mere behavior. A case of behavior (typically, a bodily movement) thus is classified as mere behavior, or as free action, 6 and free agents are those beings that can act freely. 7 For example, human beings are free agents, and they typically act freely. Most of what we do -taking a sip of coffee, walking to the store |
Traditionally, agency and freedom are most often discussed under the heading of 'free will'. There is a long discussion about the notion of free will itself as well as about its metaphysical preconditions. We will use some of the terminology that has been developed in that discussion, but in this paper we do not discuss free will. In philosophy, free will is mostly tied to specifically human traits, such as being the proper subject of moral praise and blame, or a capacity for conscious deliberation or for the linguistic expression 6 We avoid taking a stance on the thorny issue of whether some instances of mere behavior constitute actions, albeit unf |
11 This does not mean that we have to attribute free will to them, or to deny them freedom altogether when we find, quite sensibly, that they fall short of possessing free will. But neither would it be enough to attribute their behavior to them in a merely causal way. If a crow catches a worm, causal attribution is warranted, but what goes on is relevantly unlike a stone breaking a window. What we are trying to 8 See, again, O'Connor (2016) for a good overview of relevant philosophical issues. In the scientific literature, 'free will' is sometimes used less specifically than in philosophy -sometimes |
9 A note on philosophical terminology to avoid a misunderstanding: There is a large discussion about so-called 'freedom of action', meaning the absence of external obstacles (see note 2). What we are calling 'free agency' is not the same phenomenon as what is discussed as 'freedom of action'. The latter notion is employed to illustrate or even replace the notion of 'free will' when it comes to assessing human behavior. We are aiming at a much broader notion. Also, 'freedom of action' is traditionally associated with making room for freedom under the assumption of determinism (so-called compatibilism, see section |
10 On this point, see again Steward (2012). This important book has done a lot to show that the metaphysics of free agency is the proper place to discuss the issue of freedom vs. determinism. 11 We again refer to Steward (2012, esp. ch. 4) for an abundance of examples. Methodologically, it is important to note that we are here after the explication of a notion of free agency for which there is no acknowledged off-the-shelf definition. This requires us to work out the boundaries of this notion starting from clear positive and negative cases, such as cats and |
Free Agency under Indeterminism 223 explicate is a notion of free agency that allows for the attribution of an action to an agent in a way that lies between mere causal attribution and the demands of attributing an action out of free will. The former type of attribution does not distinguish a free action from a case of mere behavior: behavior of both kinds is causally attributable. The latter type of attribution, on the other hand, traditionally implicates conscious self-reflection and the possibility of moral assessment, limiting that type of attribution, for all that we know, to human beings. In order to home in on the middle-level notion |
Second, consider examples of feline agency. It may well be that for non-human animals, acting out of free will is out of the question: we do not praise or blame a cat in a moral sense. But we do make a distinction between the cat's mere behavior and her free agency. In the former case, we view that cat, as it were, mechanically; in the latter case, we attribute actions to her as an agent that wants certain things and not others, and which can be influenced through teaching. We see this distinction clearly in cases in which the cat's behavior bothers us so that we want to stop |
13 Take a case of mere behavior, e.g., the cat shedding hair on your dark carpet. In order to stop that behavior, you may decide to brush the cat, or perhaps to get her on a diet leading to less shedding: the aim is to alter the cat physically in a direct way. In a case of the cat's free agency, our attitude is different. Thus, when the cat sits down on your keyboard while you are trying to type, you may recognize that this is a bad attention-grabbing idea of hers, and try to teach her not to do it. Reacting in this way, you address |
We have already established that we attribute free agency in many cases, including cases in which we do not attribute free will, and that we dismiss the attribution of free agency in cases of mere behavior, which we attribute causally but not as agency. In building on these examples, we are assuming that the attribution of free agency tracks an important and real difference among what is going on in our world. The notion of a free agent (a system that can act freely) thus has clear instances, such as human beings, cats, and crows, and clear non-instances, such as stones, tables, and thermostats, who |
14 It is possible to acknowledge the fact that we attribute free agency while denying that there is such a thing as free agency at all. Such a skeptical option (an error theory of agency attribution) is always available, but we can dismiss it as irrelevant for our approach, which aims at establishing the possibility of free agency by presenting an explicit model. 15 A sizable part of the free will discussion at present targets notions of control, such as regulative vs. guidance control (see, e.g., Fischer and Ravizza 1998). Since the examples used in discussions of control are often subject to moral assessment, and since there |
This thought has to be unpacked in order to yield a list of criteria. We start with a precondition of all kinds of behavior: (1) causal influence. This criterion is, however, not yet specific; causal difference-making is not sufficient for free agency. Thermostats make a causal difference to what happens, but they cannot act freely. Further criteria have to be added. Guided by the above discussion, we propose the following minimal list of additional criteria: free agency has to be (2) non-rigid, (3) flexible and adaptive, and (4) sensible. We proceed to argue for our criteria in |
(3) Requiring flexibility and adaptivity is a way of spelling out in which way a free agent should be non-rigid. A thing that responds completely erratically, such as a lottery machine, is non-rigid, but we would not call such a thing a free agent. For free agents, non-rigidity plays a positive role on two different time-scales. On a short time-scale, free agents can act in a flexible way: in following through a course of action, such as moving from one place to 16 When discussing free will, it is important to count omissions and refrainings as morally attributable |
Thomas Müller and Hans J. Briegel another, a free agent has a repertoire of possible variants which are employed, e.g., to overcome obstacles. Finding a route blocked, a reflex agent may be stymied, while a free agent can vary its behavior and thereby find new ways to proceed. On a longer time-scale, free agents adapt to their environment and the feedback they receive from it: they learn, and they can be trained (they may even be able to train themselves, through practicing and playing). Free agents develop over time, and the way they have developed influences the way they act at a given time. This |
It is clear that we need to avoid talking about rightness and wrongnessmoral categories are not applicable when we limit ourselves to free agency. For intention, rationality, and the will, we do not take a stance on whether these notions can be fully accounted for on the basis of free agency alone. Rationality is sometimes tied to high-level linguistic capacities, which would limit rationality to human beings; 19 other uses of the term are less stringent. We do not wish to become tangled up in the associated terminological debate, and thus we avoid speaking of rationality. With respect to the will, the situation is similarly |
These claims are largely independent. Logical consistency dictates only that one not hold both (DetCom) and (DetInc), or both (IndCom) and (IndInc), since these pairs are contradictories. All other combinations of claims are logically consistent. Thus, somebody could argue for both (DetInc) and (IndInc), thereby proving that no matter whether the world is deterministic or indeterministic, there can be no free agency. 23 At the other end of the spectrum, one could argue for both (DetCom) and (IndCom), thus showing that there can be free agency no matter whether the world is |
The four claims differ in the manner in which they can be established. Claims (DetCom) and (IndCom) are compatibility claims. Such claims can be proved directly by example, that is, by providing an actual or a possible scenario in which both notions are instantiated. Thus, in order to establish claim (DetCom) in this direct fashion, one should describe a way the world could be like such that both determinism holds, and there is free agency. Claim (DetCom) could also be established in a somewhat weaker way, indirectly: If one knows that there can be free agency -e.g., because one knows |
Note that the dialectical situation we have sketched so far is completely symmetrical between the notions of determinism and indeterminism. For both metaphysical positions, there is a compatibility claim and an incompatibility claim, and the methods for establishing such claims are exactly parallel. The only further remark we can make at this point is that prima facie, it should be easier to establish claim (IndCom) than claim (DetCom). In order to establish claim (DetCom), one has to present a scenario in which both determinism and free agency are exemplified, and since determinism is an extraordinarily strong constraint on ways |
Given the layout of the dialectical landscape just described, we can now say precisely what the aim of our paper is: We aim to establish claim (IndCom) of the compatibility of indeterminism and free agency, via a direct route: We will provide a possible scenario in which both free agency and indeterminism can be exemplified. (Actually, we provide more than is strictly required for the compatibility claim: We do not just exhibit one instance, but a generic possibility via a whole class of models.) In this paper we do not take a stance on the compatibility question for determinism. 29 And we make no assumptions |
30 28 In fact, with a view to the cheapshot strategy mentioned in note 27, it seems nearly impossible to establish claim (IndInc) without thereby also establishing claim (DetInc). That is, those who hold on to the possibility of free agency can hardly hope to establish the impossiblity of free agency under indeterminism (claim (IndInc)), at least without distorting the claim of universal determinism. On the other hand, it might be possible to establish claim (DetInc) without thereby having to deny the possibility of free agency completely. We stress again that there are many ways for indetermin |
Given that the dialectical situation is tidy and symmetrical, it is unfortunate that the terminology that has been established, especially in the recent free will debate, suggests asymmetries between the compatibility claims (DetCom) and (IndCom). An asymmetric treatment has become well entrenched in the debate, but as we will show, the asymmetries are spurious and in fact distort the debate. Consider the labels used for major positions in the free will debate. 31 First, it is striking that the label 'compatibilism' is reserved for claim (DetCom) of the compatibility of free agency and determinism, but that |
34 As a symptom of the fact that the debate fails to reflect the symmetry of the positions, one can note that many simulations. There is universal agreement that the gold standard for certified randomness is so-called device-independent randomness, which is directly tied to the assumption of the fundamentality of quantum-mechanical indeterminism. See Acín and Masanes (2016) for an overview, and see note 44 below for a reference to a prominent current implementation effort. The reasoning behind these massive efforts is that only indeterminism at the ontological level can secure true randomness. Before this background, we hold that an interesting critique of |
32 Belnap et al. (2001, 204) note that it would be better if claim (IndCom) were called 'compatibilism': It is the more important compatibility claim, as it pertains to our arguably indeterministic world. We agree that there should be a separate label for claim (IndCom), and that 'compatibilism' would be an apt label, but we will not attempt to change the long-established terminology here. (Neither do Belnap et al.) 33 As we said, Steward (2012, 13 ) labels her own position as 'Agency Incompatibilism |
Thomas Müller and Hans J. Briegel systematic overviews of possible positions in the free will debate, such as Fischer et al. (2007), are structured around the compatibility or incompatibility of various claims with determinism only. Given such an approach, the possible positions with respect to free agency can be given as a 2 × 2 matrix as shown in Table 1. This table reflects the traditional, century-old concern that determinismwhether motivated scientifically, theologically, or otherwise -might pose a threat for our freedom. Assuming the truth of determinism, there are, accordingly, specific labels for the compat |
In our view, libertarianism is not a helpful alternative to compatibilism because it is too specific, combining three (or even four) logically independent claims under one label. Of course, such a package deal is dialectically more fragile than compatibilism, since it can be attacked in many different ways, especially since it spans both action theory (in view of the compatibility and incompatibility 35 See Wiggins (1973). Note that Kane (1998, 13) phrases his 'intelligibility question' in the following way: "Can we make sense of a freedom or free will that is incompatible with |
This table shows that, as we remarked above, a position that falls under the traditional label of compatibilism is not yet fully detailed: Compatibilism (DetCom) stands for the upper row of the table, which comprises two fully specified positions, (A) and (B). Of these, position (B) is the position advocated in the title of a paper that puts forward what has become known as the "Mind argument" 38 (Hobart 1934) : "Free will as involving determination and inconceivable without". Not all compatibilists nowadays want to hold on to such a position |
38 That name is due to the fact that the paper, and other papers with similar claims, appeared in the journal, Mind, in the 1930s. See Van Inwagen (1983, 16 ) and Franklin (2011) for the terminology. 39 In that case, however, they will have to argue for claim (IndCom) in order to avoid commitment to position (B). 40 Such agnostic compatibilists are thus also facing the task to which this paper is devoted. They should therefore welcome the model we are proposing in this paper. At any rate, the reality of agency |
Here is a first way in which randomness can be useful for an agent. The model to be described below goes far beyond this, but we offer the following considerations as a first step toward the idea that as an agent, randomness can be your friend. Consider tie-breaking: An agent is in a situation in which a particular choice has to be made, but the actual choice does not matter. Famously, this is the situation of Buridan's ass situated symmetrically between two equally attractive stacks of hay. Since there is nothing in the situation to tip the balance one 39 For example, writing about free will rather than free agency, |
Free Agency under Indeterminism 235 way or the other, the creature has to find a way to break the tie if it wants to avoid starvation. Randomness can come in handy here: It is perfectly appropriate to tie the tie-breaking to some random event. And this is so independently of whether the randomness can be traced back to some microscopic happening in the agent's brain, or whether it is enforced by tossing a coin (or, better, sending a photon through a beam splitter). So, given that agents from time to time are facing choices whose outcome does not matter, having a built-in random tie-breaking mechanism would be helpful |
Here is a next kind of situation in which randomness can really help an agent in a specific and crucial way. Animals trying to escape from a predator will be caught easily if their escape behavior is predictable. So it has great survival value for typical prey to show erratic, unpredictable escape behavior. And such behavior is found in many experimental studies, e.g., in cockroaches and in flies. 43 Here the task is not just tie-breaking (the animal has to run away in some direction rather than stay where it is), but tie-breaking in an unpredictable way (the predator should not be able to guess which direction and which path the |
Still, these tie-breaking examples only show that randomness can be useful for an agent in the sense that successful agents will profit from having sources of randomness available to handle special types of situations. 44 A model for free agency under indeterminism should provide more if it is to make a positive contribution in 42 Ironically, it seems that among the best candidates for mere tie-breaking situations we find the experimental settings of neuroscientific free-will experiments such as Soon et al. (2008). In that experiment, participants have to choose, roughly equally, between the two options of clicking left or right. Whether you click left or right |
Thomas Müller and Hans J. Briegel the current debate about free agency: Such a model should not stop at making the general point that randomness can be a useful resource, but show explicitly how randomness can be a useful element in the dynamical coming to be of an individual, specific action. At this point, two approaches are available. The common approach is to start with a basically deterministic model of agency, such as offered, e.g., by various compatibilist analyses of agency, and add a random element at the right place of the causal history. 45 This, in turn, could take the form of showing how such |
The other approach, which we call deeply stochastic agency modeling, is not to start with a deterministic model at all, but to work out a stochastic model, in which indeterminism is the central resource for the model's dynamics. Stochastic models are well known in the sciences. Important examples include Einstein's explanation of Brownian motion (Einstein 1905 ) and Fisher's model of natural selection in population genetics (Fisher 1930). Such models have a broad range of applications both in the natural and social sciences (Van Kampen 2007; Gardiner 2009 ). In what follows, we propose such |
We now describe a stochastic process model of free agency under indeterminism based on an associative memory organization and random option selection. The 45 All the options for indeterministic theories of agency discussed in the overview by Franklin (2011), e.g., the so-called 'deliberative libertarian' theories of Mele (1999) and of Clarke (2000), are of that type. 46 See, e.g., Fischer and Ravizza (1998, 253). 47 See, e.g., Kane (1998, ch. 5) on'self-forming actions' as ind |
The basic process of deliberation for a PS agent can be expressed within the percept-action framework of artificial agents (Russell and Norvig 2011) and goes as follows. Given a specific state (topology and weights structure) of the ECM and triggered by some perceptual input, a first memory clip is activated. Subsequently, a random walk through the clip network ensues, involving a number of transitions that is not determined beforehand, until activation is coupled out, triggering some motor action. The random walk through the clip network follows the weights (probabilities) as specified in the given state of the ECM. In Figure |
Thomas Müller and Hans J. Briegel history and thus encode her past experience connecting sensory input to action output, including the consequences (good or bad) that these actions had for the agent. Weights are updated after an action has been performed and feedback has been received (as part of the perceptual input), e.g., by strengthening those connections that were activated during the random walk leading from percept to rewarded action. The updating of the ECM may also include the stochastic generation of new clips through variation or composition of existing ones, which changes the topology and size of the associative network. This provides additional flexibility for the agent to develop different |
In one run of projective simulation, a given percept as input at time t 0 can lead to any of a number of actions as outputs, and output can be triggered at different times t 0 + mΔt corresponding to a deliberation length of m transitions (each taking the time Δt, assuming a simple model with uniform dynamics). Various refinements and extensions of the model are possible and have been explored. These include different learning schemes, e.g., with the capacity to generalize (Melnikov et al. 2017), or with meta-learning, which involves the adaptation of the learning parameters themselves ( |
First, it is clear that the model is indeterministic -it is based on an indeterministic random walk for each coupling of sensory input (percept) to motor output (action). It should also be noted that this indeterministic aspect is a fundamental feature of the model in the same way in which other well-known models in physics, such as the ones referred to at the end of section 3.1, are fundamentally indeterministic. In projective simulation, the indeterminism is not added on top of an 50 Recent developments include applications in robotics (Hangl et al. 2016 (Hang |
We proceed by establishing that the model meets the criteria for free agency laid out in section 2.1.2. Thus, we have to argue that the actions of a PS agent can be causally relevant, non-rigid in a flexible and adaptive way, and sensible. Causal relevance is clear since a run of projective simulation is itself a causal process that terminates in some action. The non-rigidity of actions is also obvious: Given one and the same perceptual input and the same internal state, several actions are possible -the agent's behavior is not a hard-coded reflex. Over a short time-scale, that |
Thomas Müller and Hans J. Briegel In favor of our claim that a PS agent's actions are sensible, we can offer two main arguments that relate to the mentioned two different time-scales. First, while the projective simulation process is indeterministic, each single instance of that process makes sense before the background of the agent's learning history reflected in the transition weights and, more generally, in its memory structure at the given time. On the short time-scale of an individual action, a single stochastic process leading from sensory input to that action represents the dynamical succession of considerations in the agent's associative memory structure. Each clip |
Second, on the longer time-scale of learning and forming behavioral dispositions, each individual deliberation-action process makes sense because it contributes to the agent's individual history and to its development as an agent. Each such process allows for learning through the feedback (in the simplest reinforcement learning scheme, a perceived reward) that the agent receives from the environment. That feedback first of all affects the transition weights between clips that were activated during the actual deliberation process. Furthermore, as part of the projective simulation scheme, new clips may be created out of already existing ones, which need not correspond to any factual experience in the agent's past. If |
Also related to the longer time-scale of learning, we can note that based on indeterministic decision processes with learning through feedback, a PS agent can develop (almost) deterministic reactions to specific stimuli. PS agents thus need not be unreliable or haphazard. In some cases they can exhibit behavior typical of hard-coded routines (even starting from quite arbitrary connection weights in their memory): given proper reinforcement, an agent can, as it were, learn to become a rigorist about certain forms of behavior in specific circumstances. This allows the model to capture in a sensible way the dynamics of building up strong habits, or a firm character, as |
Within the PS model, therefore, we use indeterminism as a central and basic resource. Importantly, this does not mean that we expose an otherwise deterministic agent to certain random processes. The PS model is not based on an underlying deterministic deliberating agent that is somehow 'randomized' to arrive at the model in a second step. The random processes we are referring to here are not something external that would randomize the agent's actions (as if the agent was given independently and beforehand, and then perhaps enslaved by outside randomness). On the contrary, the random processes form a constitutive element of the agent's memory and the very |
It should be pointed out that the model of projective simulation, including its rules for transitions and compositions in clip space, represents a specific model of reinforcement learning in a physically inspired approach to (quantum) artificial intelligence. It is meant to be a simple model for natural and artificial agents that can learn and show flexible and sensible behavior. We do not claim to give an account of any deeper or more advanced aspects of human agency such as free will. For our purposes, projective simulation serves as a formal model of free agency, where the process of decision finding that precedes an action in a given learning environment can be mapped out in |
Our description of the PS model and of its interpretation so far has been fairly abstract. In order to balance our description, we now give an (oversimplified) example of the dynamics of projective simulation in which the abstract talk of considerations is tied to a concrete situation. Here is our little story: We assume that while you are typing at your sunny desk, your cat is sitting on the floor and 51 In the free will debate, indeterminism-based accounts (i.e., libertarian theories) are often confronted with a 'challenge from luck', one aspect of which is exactly how to account for a firm moral character in the face |
We interpret these clips in the cat's memory, with reference to our little story, as follows: Percept s represents the situation that the cat is in: sitting on the floor, sunlight on the desk, her owner sitting at the desk typing. Action a 1 represents jumping, action a 2, walking away. The given percept s triggers consideration c 0 with probability p(c 0 | s) = 1. The associative considerations linking percept s to one of the actions a 1 or a 2 in the stochastic ECM network are interpreted as follows. Consideration c 0 represents remembered episodes of the cozy feeling |
Based on this network structure and given specific values for all the mentioned transition probabilities, we can describe the fine structure of the cat's possible courses of deliberation and action quantitatively. In order to simplify the math, let us assume that all transitions from a given node have equal weight, such that, for example, both possible transitions from clip c 1 -jumping (a 1 ) or arriving at the next consideration c 2 -have equal probability of p a 1 jc 1 ð Þ¼p c 2 jc 1 ð Þ¼ 1 2. An agent who has |
Given our simple stochastic dynamics, the total probability that the cat's deliberation will finally lead to jumping at some time after the time of the percept s, t 0, under the assumed weights, is the sum of the probabilities of all paths leading to jumping, which comes down to p jump = 6/7. The probability for walking away is, Table 3 jump or walk away? In the given model, jumping can occur immediately, after two steps (each of duration Δt), at time t 0 + 2Δt, but also after a much longer deliberation time, e.g., after 12 |
With our toy model we have illustrated a simple memory structure of considerations leading from perception to action via different paths. In Table 3 we have shown some of these paths in detail, including values for the paths' probabilities. These paths provide an internal description of the stochastic development of the agent's considerations. We have also given an external description of which actions the stochastic development leads to (the mere input -output coupling), both for the individual paths differentiated internally (see the right-hand column in Table 3 ) and in aggregate fashion (see the values for p jump and for p walk away given above). Before this detailed background, is it |
The basic worry behind any form of the luck objection is that if something happens indeterministically, it is due to chance, and thus not due to an agent. In this general form, the objection is easily dismissed -it construes chance as an agent herself and then invokes a rivalry between being due to chance and being due to the agent in question. However, calling something 'due to chance' is not yet an analysis, but a metaphorical redescription. A lot more has to be said in order to show that the mere occurrence of an indeterministic event in the history of a happening disqualifies that happening from being |
Van Inwagen's replay argument is more specific than the two variants of the luck objection just mentioned, and therefore more serious. He considers a real action at some time (think of the cat walking away at time t 0 + 4Δt) and the indeterministic real possibilities at some previous time (think of the cat registering percept s at time t 0 ). Van Inwagen prompts us to imagine the situation to be replayed 100 times from time t 0 on, and then to record the frequencies of the occurrence of the various possible actions. These frequencies can be interpreted as probabilities, and this shows |
The replay argument, on the other hand, is phrased in terms of an external description that only considers the final step of the dynamics, which results in the action. This description lacks the detail to make an individual run understandable and thereby attributable. The external description shields the resulting action from the actual dynamics and thereby provides a description that indeed only offers an interpretation of what is going on as a chance process. But for a PS agent, such a description lacks the crucial detail of the internal dynamics. And apart from this structural point, there is also an important quantitave point to be made about the timing of actions. In our |
58 Second, the different actions need not be alternatives for the exact same time. In fact, in the network of Figure 2, if clip c 1 is activated, 57 We repeat that the replay argument is originally given in the context of a discussion of free will. In fact, Van Inwagen's actual example is of a woman who has to make a morally important choice about either lying or telling the truth. The woman, Alice, in fact tells the truth, but according to Van Inwagen, a consideration of possible replays shows that we cannot praise Alice for her actual truthtelling, given that |
Free Agency under Indeterminism 247 action a 1 can result immediately, but the immediate alternative to action a 1 is not action a 2 (which would not make sense as flowing from the consideration c 1 ), but the associative activation of a different consideration, c 2, which can then lead to action a 2 in a sensible way. Thus, the immediate alternative to a certain action is normally not a different action, but rather reconsidering, or continuing to deliberate. 59 In fact, already in our toy model, one of the alternatives to action a 1 at time t is the same action, |
Note that even if the agent's memory structure is such that the actions a 1 and a 2 in the end both occur with a probability of 1 2, 61 it is not adequate to think of the agent as tossing a fair coin to decide what to do. The indeterministic decision process does not just provide an outcome satisfying certain statistics, but in each and every run provides a path of considerations that is shaped by the agent's past experience. A coin toss would not do that; it would destroy the sensibility of the agent's action. And it would also not provide a foothold for the longer-term |
In this paper, we have proposed a novel approach to the question whether there can be free agency under indeterminism. That question is of crucial importance for our practical self-conception and for the freedom debate: There are good reasons to assume that our world is indeterministic, and we consider ourselves to be free agents in that world, so we should understand in which way our freedom could be compatible with indeterminism. That question is surprisingly little discussed. The novelty of our approach lies in the aim we set ourselves and in the chosen means. Our aim was to argue only for a positive compatibility claim: for the compatibility of free |
With respect to means, we opted for the direct route to establishing our compatibility claim via an explicit, mathematically well-defined and physically motivated class of models. We described the agency model of projective simulation and argued that it exhibits the sought-for combination of free agency and indeterminism. Thus our main argument is a constructive one, exhibiting examples of what we claim to be possible. In section 4.3 we also discussed a possible counterargument against our compatibility claim, Van Inwagen's replay argument. We showed that that argument cuts no ice with us, since the internal stochastic dynamics of the PS model provides an adequate representation |
In 1974, Peter Doherty and Rolf Zinkernagel published a landmark article in Nature [1] that described the ability of lymphocytic choriomeningitis virus (LCMV)-specific cytotoxic T cells to lyse LCMV-infected, 51 Cr-labeled target cells if the target cells shared class I major histocompatibility complex (MHC) molecules with these T cells. Surprisingly, infected and labeled target cells with disparate class I MHC molecules were not lysed. This phenomenon, which came to be known as "MHC restriction," was a major advance in our |
Sure, it's a medical problem, but is a solution likely to come from focusing on this issue? How would you take it forward, either conceptually or practically? NG Specifically, would you accept a slight re-statement of MHC restriction such as the following: T cells recognize nominal (eg, viral) antigen in association with self MHC molecules (of the appropriate class) and a subset of nonself molecules of the same class that are highly similar to self MHC molecules in primary structure? This perspective suggests that MHC restriction is ultimately best viewed as probabilistic because recognition by T-cell receptors (TCR), like antibodies |
As I recall, I don't think Kindred and Shreffler concluded anything much and I know, for a fact, that (in 1975 at least) Don Shreffler (who was a good guy) thought our ideas were crazy. Katz and Benacerraf had come to some very premature conclusions regarding the "Ir gene products" (they thought they were the TCRs) that led them down the wrong path. César Milstein called them on this, but it was only when Benacerraf heard me talk in Boston, then saw our subsequent Nature and Lancet articles that he changed his |
In 1995, after you won the Lasker Basic Medical Research Award [7], I congratulated you and expressed the view that you and Rolf deserved the recognition associated with a Nobel Prize despite my concerns about the limitations of such awards. What are your thoughts about your contribution, with Rolf, to elucidating the nature of antigen recognition by T cells versus the contributions of those such as Kindred and Shreffler [5], Katz and Benacerraf [6], Michael Bevan [8], Gene Shearer [9], and Ethan Shevach and Alan Rosenthal? [10 |
ith Ibn Sina great Canon came the "golden age of Arabic medicine", almost to its peak. Since the beginning of XI century, when Ibn Sina died, until the middle of XIII century, when creative was Ibn al-Nafis, medical science continues to develop and progress, and had its brilliant minds. For that time characteristic is the fact that neither the strong authority as Avicenna was could paralyze the progress of medical science. Three hundred years before Paracelsus, in Cairo appears a medical scientist who dares to touch the authority of Ibn Sina-Avicenna in the infallibility of Canon-"Medical |
He was born in the year 1210 in a village near Damascus called "Quersh' (1,2,3,4,5,6,7.8.9.10). He joins the circles of medicine at the age of 22 (in the year on occasion of 800th anniversary of Birth of ibn al-nafis -discoverer of Cardiac and Pulmonary Circulation 1232) in Aldakhoiriah School. Given the name of its founder; Al-Dakhwar (Died 1231). He studied the books of famous pioneers Muslims physicians such as Rhazes |
Ibn-Nafis lived in an age of political conflicts and chaos in the Muslim world-the rivality of dynasties, wars, and devastating invasion of the Mongols. However, despite all this, the academic activities in Damascus and Cairo were not significantly weakened, particularly in the field of medicine, for which there are obvious evidences of a permanent functioning of medical schools and hospitals. One of the major scholars who have dealt with this issue, Leclerc, notes that the medicine has progressed particular in this period. Regardless of political conflicts and wars still continued the construction of schools and hospitals, where they were guarded the traditional standards |
Ibn-Nafis wrote article about the pulse, which is important in terms of Ibn-Nafis learning influence in the West and the establishment of prominent medical schools. This work is not preserved in its original form, but it appears in Latin translation in the early 16th century. A doctor from that era Andrea Alpago is credited for the transmission of Ibn-Nafis theory of lung (small) circulation in the West. As Alpago maintained links with the University of Padua, assume that the Italian school of anatomy, as well as Michael Servetus, claimed Ibn-Nafis theory from one of Latin translations |
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