3,774 research outputs found
How objective are biological functions?
John Searle has argued that functions owe their existence to the value that we put into life and survival. In this paper, I will provide a critique of Searle’s argument concerning the ontology of functions. I rely on a standard analysis of functional predicates as relating not only a biological entity, an activity that constitutes the function of this entity and a type of system but also a goal state. A functional attribution without specification of such a goal state has no truth-value. But if completed with a goal state, functional attributions understood as four-place relations attain a truth-value. The truth conditions of all attributions of function involve a dependence claim of the goal state on the function bearer’s activity. The nature of this dependence may differ; I consider five different possibilities: causality, mechanistic constitution, mereology, supervenience and metaphysical grounding. If these dependency relations are objective, Searle’s central ontological thesis fails. What he ought to have said is that our valuing survival or other goal states may be the reason why biology seeks functional knowledge, but this has nothing to do with ontology. I will show further that Searle also raised an interesting challenge concerning the relationship of functional and causal truths, but it does not threaten the objectivity of functions either. At best, it could show that functional vocabulary is eliminable. However, I will show that functional vocabulary is not so eliminable
Which Kind of Causal Specificity Matters Biologically?
Griffiths et al. (2015) have proposed a quantitative measure of causal specificity and used it to assess various attempts to single out genetic causes as being causally more specific than other cellular mechanisms, for example, alternative splicing. Focusing in particular on developmental processes, they have identified a number of important challenges for this project. In this discussion note, I would like to show how these challenges can be met
Thought Experiments in Biology
Unlike in physics, the category of thought experiment is not very common in biology. At least there are no classic examples that are as important and as well-known as the most famous thought experiments in physics, such as Galileo’s, Maxwell’s or Einstein’s. The reasons for this are far from obvious; maybe it has to do with the fact that modern biology for the most part sees itself as a thoroughly empirical discipline that engages either in real natural history or in experimenting on real organisms rather than fictive ones. While theoretical biology does exist and is recognized as part of biology, its role within biology appears to be more marginal than the role of theoretical physics within physics. It could be that this marginality of theory also affects thought experiments as sources of theoretical knowledge. Of course, none of this provides a sufficient reason for thinking that thought experiments are really unimportant in biology. It is quite possible that the common perception of this matter is wrong and that there are important theoretical considerations in biology, past or present, that deserve the title of thought experiment just as much as the standard examples from physics. Some such considerations may even be widely known and considered to be important, but were not recognized as thought experiments. In fact, as we shall see, there are reasons for thinking that what is arguably the single most important biological work ever, Charles Darwin’s On the Origin of Species, contains a number of thought experiments. There are also more recent examples both in evolutionary and non-evolutionary biology, as we will show. Part of the problem in identifying positive examples in the history of biology is the lack of agreement as to what exactly a thought experiment is. Even worse, there may not be more than a family resemblance that unifies this epistemic category. We take it that classical thought experiments show the following characteristics: They serve directly or indirectly in the non-empirical epistemic evaluation of theoretical propositions, explanations or hypotheses. Thought experiments somehow appeal to the imagination. They involve hypothetical scenarios, which may or may not be fictive. In other words, thought experiments suppose that certain states of affairs hold and then try to intuit what would happen in a world where these suppositions are true. We want to examine in the following sections if there are episodes in the history of biology that satisfy these criteria. As we will show, there are a few episodes that might satisfy all three of these criteria, and many more if the imagination criterion is dropped or understood in a lose sense. In any case, this criterion is somewhat vague in the first place, unless a specific account of the imagination is presupposed. There will also be issues as to what exactly “non-empirical” means. In general, for the sake of discussion we propose to understand the term “thought experiment” here in a broad rather than a narrow sense here. We would rather be guilty of having too wide a conception of thought experiment than of missing a whole range of really interesting examples
The Crux of Crucial Experiments: Duhem's Problems and Inference to the Best Explanation
Going back at least to Duhem, there is a tradition of thinking that crucial experiments are impossible in science. I analyse Duhem's arguments and show that they are based on the excessively strong assumption that only deductive reasoning is permissible in experimental science. This opens the possibility that some principle of inductive inference could provide a sufficient reason for preferring one among a group of hypotheses on the basis of an appropriately controlled experiment. To be sure, there are analogues to Duhem's problems that pertain to inductive inference. Using a famous experiment from the history of molecular biology as an example, I show that an experimentalist version of inference to the best explanation (IBE) does a better job in handling these problems than other accounts of scientific inference. Furthermore, I introduce a concept of experimental mechanism and show that it can guide inferences from data within an IBE-based framework for induction. Introduction Duhem on the Logic of Crucial Experiments ‘The Most Beautiful Experiment in Biology' Why Not Simple Elimination? Severe Testing An Experimentalist Version of IBE 6.1Physiological and experimental mechanisms 6.2Explaining the data 6.3IBE and the problem of untested auxiliaries 6.4IBE-turtles all the way down Van Fraassen's ‘Bad Lot' Argument IBE and Bayesianism Conclusion
Critical notice: Darwinian reductionism
This notice provides a critical discussion of some of the issues from Alex Rosenberg's Darwinian Reductionism, in particular proper functions and the relationship of proximate and ultimate biology, developmental programs and genocentrism, biological laws, the principle of natural selection as a fundamental law, genetic determinism, and the definition of "reductionism.
Causal Selection vs Causal Parity in Biology: Relevant Counterfactuals and Biologically Normal Interventions
Causal selection is the task of picking out, from a field of known causally relevant factors, some factors as elements of an explanation. The Causal Parity Thesis in the philosophy of biology challenges the usual ways of making such selections among different causes operating in a developing organism. The main target of this thesis is usually gene centrism, the doctrine that genes play some special role in ontogeny, which is often described in terms of information-bearing or programming. This paper is concerned with the attempt of confronting the challenge coming from the Causal Parity Thesis by offering principles of causal selection that are spelled out in terms of an explicit philosophical account of causation, namely an interventionist account. I show that two such accounts that have been developed, although they contain important insights about causation in biology, nonetheless fail to provide an adequate reply to the Causal Parity challenge: Ken Waters's account of actual-difference making and Jim Woodward's account of causal specificity. A combination of the two also doesn't do the trick, nor does Laura Franklin-Hall's account of explanation (in this volume). We need additional conceptual resources. I argue that the resources we need consist in a special class of counterfactual conditionals, namely counterfactuals the antecedents of which describe biologically normal interventions
Discussion Note: Which Kind of Causal Specificity Matters Biologically?
Griffiths et al. (2015) have proposed a quantitative measure of causal specificity and used it to assess various attempts to single out genetic causes as being causally more specific than other cellular mechanisms, for example, alternative splicing. Focusing in particular on developmental processes, they have identified a number of important challenges for this project. In this discussion note, I would like to show how these challenges can be met
The Conserved Dcw Gene Cluster of R. sphaeroides Is Preceded by an Uncommonly Extended 5 Leader Featuring the sRNA UpsM
Cell division and cell wall synthesis mechanisms are similarly conserved among bacteria. Consequently some bacterial species have comparable sets of genes organized in the dcw (division and cell wall) gene cluster. Dcw genes, their regulation and their relative order within the cluster are outstandingly conserved among rod shaped and gram negative bacteria to ensure an efficient coordination of growth and division. A well studied representative is the dcw gene cluster of E. coli. The first promoter of the gene cluster (mraZ1p) gives rise to polycistronic transcripts containing a 38 nt long 5 UTR followed by the first gene mraZ. Despite reported conservation we present evidence for a much longer 5 UTR in the gram negative and rod shaped bacterium Rhodobacter sphaeroides and in the family of Rhodobacteraceae. This extended 268 nt long 5 UTR comprises a Rho independent terminator, which in case of termination gives rise to a non-coding RNA (UpsM). This sRNA is conditionally cleaved by RNase E under stress conditions in an Hfq- and very likely target mRNA-dependent manner, implying its function in trans. These results raise the question for the regulatory function of this extended 5 UTR. It might represent the rarely described case of a trans acting sRNA derived from a riboswitch with exclusive presence in the family of Rhodobacteraceae
Derivation of Del180 from sediment core log data\u27 Implications for millennial-scale climate change in the Labrador Sea
Sediment core logs from six sediment cores in the Labrador Sea show millennial-scale climate variability during the last glacial by recording all Heinrich events and several major Dansgaard-Oeschger cycles. The same millennial-scale climate change is documented for surface water δ18O records of Neogloboquadrina pachyderma (left coiled); hence the surface water δ18O record can be derived from sediment core logging by means of multiple linear regression, providing a paleoclimate proxy record at very high temporal resolution (70 years). For the Labrador Sea, sediment core logs contain important information about deepwater current velocities and also reflect the variable input of ice-rafted debris from different sources as inferred from grain-size analysis, the relation of density and P wave velocity, and magnetic susceptibility. For the last glacial, faster deepwater currents, which correspond to highs in sediment physical properties, occurred during iceberg discharge and lasted from several centuries to a few millennia. Those enhanced currents might have contributed to increased production of intermediate waters during times of reduced production of North Atlantic Deep Water. Hudson Strait might have acted as a major supplier of detrital carbonate only during lowered sea level (greater ice extent). During coldest atmospheric temperatures over Greenland, deepwater currents increased during iceberg discharge in the Labrador Sea, then surface water freshened shortly thereafter, while the abrupt atmospheric temperature rise happened after a larger time lag of ≥ 1 kyr. The correlation implies a strong link and common forcing for atmosphere, sea surface, and deep water during the last glacial at millennial timescales but decoupling at orbital timescales
Auswirkungen des flächendeckenden Mindestlohns auf die gewerbliche Wirtschaft im Freistaat Sachsen
Am 1. Januar 2015 wurde in Deutschland ein flächendeckender, gesetzlicher Mindestlohn in Höhe von 8,50 Euro je Stunde eingeführt. Dieser soll zum 1. Januar 2017 erstmals angepasst werden. Die Anpassung soll dabei laut Mindestlohngesetz die Auswirkungen des Mindestlohns auf den Mindestschutz der Arbeitnehmerinnen und Arbeitnehmer, auf die Wettbewerbsbedingungen und auf das Beschäftigungsniveau berücksichtigen. Besonders umfangreiche Wirkungen sind im Freistaat Sachsen zu erwarten, da der Mindestlohn hier eine besonders hohe Reichweite entfaltet. Vor diesem Hintergrund hat die Industrie- und Handelskammer Chemnitz die Dresdner Niederlassung des ifo Instituts beauftragt, die bisherigen Auswirkungen des flächendeckenden Mindestlohns in der gewerblichen Wirtschaft im Freistaat Sachsen zu untersuchen
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