1,721,032 research outputs found
Safety vs. efficacy assessment of pharmaceuticals: Epistemological rationales and methods
No full textAbstractIn their comparative analysis of Randomised Clinical Trials and observational studies, Papanikoloau et al. (2006) assert that “it may be unfair to invoke bias and confounding to discredit observational studies as a source of evidence on harms”. There are two kinds of answers to the question why this is so. One is based on metaphysical assumptions, such as the problem of causal sufficiency, modularity and other statistical assumptions. The other is epistemological and relates to foundational issues and how they determine the constraints we put on evidence. I will address here the latter dimension and present recent proposals to amend evidence hierarchies for the purpose of safety assessment of pharmaceuticals; I then relate these suggestions to a case study: the recent debate on the causal association between paracetamol and asthma. The upshot of this analysis is that different epistemologies impose different constraints on the methods we adopt to collect and evaluate evidence; thus they grant “lower level” evidence on distinct grounds and at different conditions. Appreciating this state of affairs illuminates the debate on the epistemic asymmetry concerning benefits and harms and sets the basis for a foundational, as opposed to heuristic, justification of safety assessment based on heterogeneous evidence
The precautionary principle in the pharmaceutical domain: A philosophical enquiry into probabilistic reasoning and risk aversion
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Causing something to be one way rather than another: Genetic Information, causal specificity and the relevance of linear order.
Full text linkPurpose
The purpose of this paper is to suggest a definition of genetic information by taking into account the debate surrounding it. Particularly, the objections raised by Developmental Systems Theory (Griffiths, 2001; Oyama 1985; Griffiths and Knight 1998) to Teleosemantic endorsements of the notion of genetic information (Sterelny et al. 1996; Maynard Smith, 2000; Jablonka, 2002) as well as deflationist approaches which suggest to ascribe the notion of genetic information a heuristic value at most, and to reduce it to that of causality (Godfrey-Smith, 2000; Boniolo, 2003, 2008).
Design/methodology/approach
The paper presents the notion of genetic information through its historical evolution and analyses it with the conceptual tools offered by philosophical theories of causation on one side (“causation as influence,” Woodward, 2010; Waters, 2007; Lewis, 2000) and linguistics on the other (“double articulation” Martinet, 1960).
Findings
The concept of genetic information is defined as a special kind of cause which causes something to be one way rather than another, by combining elementary units one way rather than another. Tested against the notion of “genetic error” this definition demonstrates to provide an exhaustive account of the common denominators associated with the notion of genetic information: causal specificity; combinatorial mechanism; arbitrariness.
Originality/value
The definition clarifies how the notion of information is understood when applied to genetic phenomena and also contributes to the debate on the notion of information, broadly meant, which is still affected by lack of consensus (Floridi, 2013)
Roundtable on Philosophy of Evidence: "Dimensions of Evidence and Criteria for Standards Improvement"
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Modus Tollens probabilized: deductive and Inductive Methods in medical diagnosis
Full text linkMedical diagnosis has been traditionally recognized as a privileged field of application for so called probabilistic induction.
Consequently, the Bayesian theorem, which mathematically formalizes this form of inference, has been seen as the most adequate
tool for quantifying the uncertainty surrounding the diagnosis by providing probabilities of different diagnostic hypotheses,
given symptomatic or laboratory data. On the other side, it has also been remarked that differential diagnosis rather works by exclusion,
e.g. by modus tollens, i.e. deductively. By drawing on a case history, this paper aims at clarifying some points on the issue. Namely:
1) Medical diagnosis does not represent, strictly speaking, a form of induction, but a type, of what in Peircean terms should be
called ‘abduction’ (identifying a case as the token of a specific type); 2) in performing the single diagnostic steps, however, different
inferential methods are used for both inductive and deductive nature: modus tollens, hypothetical-deductive method, abduction;
3) Bayes’ theorem is a probabilized form of abduction which uses mathematics in order to justify the degree of confidence which
can be entertained on a hypothesis given the available evidence; 4) although theoretically irreconcilable, in practice, both the hypothetical-
deductive method and the Bayesian one, are used in the same diagnosis with no serious compromise for its correctness; 5)
Medical diagnosis, especially differential diagnosis, also uses a kind of “probabilistic modus tollens”, in that, signs (symptoms or
laboratory data) are taken as strong evidence for a given hypothesis not to be true: the focus is not on hypothesis confirmation, but
instead on its refutation [Pr (¬ H/E1, E2, …, En)]. Especially at the beginning of a complicated case, odds are between the hypothesis
that is potentially being excluded and a vague “other”. This procedure has the advantage of providing a clue of what evidence to
look for and to eventually reduce the set of candidate hypotheses if conclusive negative evidence is found. 6) Bayes’ theorem in the
hypothesis-confirmation form can more faithfully, although idealistically, represent the medical diagnosis when the diagnostic itinerary
has come to a reduced set of plausible hypotheses after a process of progressive elimination of candidate hypotheses; 7) Bayes’
theorem is however indispensable in the case of litigation in order to assess doctor’s responsibility for medical error by taking into
account the weight of the evidence at his disposal
The epistemic nature of package leaflet information
Full text linkPackage leaflets (PL) belong to the complex communication system related to the minimization and prevention of pharmaceutical risk. Their legal nature is not exhausted by safety regulation though: as a privileged form of product instruction, they are also subject to liability regulation with a consequent reallocation of damage responsibility through risk disclosure. This article presents the results of a doctoral dissertation devoted to the legal and communicative analysis of PL information. After illustrating the articulation of pharmaceutical risk through risk prevention norms (residual risk, development risk), the paper goes on with a discussion of the PL role within the therapeutic decision as a complementary vehicle to doctor’s information. It results that the liability framework in which both information channels are embedded determines a communication model, which far from promoting a shared decision process, radicalizes the two-step communication structure typical of the informed consent model inherited by surgery judicature. The second part investigates PL information as a source of knowledge updating through the methodological tools provided by Bayesian decision theory. Finally, an empirical study conducted over a sample of 55 drug consumers investigates the impact of PL information on drug risk perception and its perceived value to therapeutic decision
Hunting Side Effects and Explaining Them: Should We Reverse Evidence Hierarchies Upside Down?
Full text linkPhilosophical discussions have critically analysed the methodological pitfalls and epistemological implications of evidence assessment in medicine, however they have mainly focused on evidence of treatment efficacy. Most of this work is devoted to statistical methods of causal inference with a special attention to the privileged role assigned to randomized controlled trials (RCTs) in evidence based medicine. Regardless of whether the RCT’s privilege holds for efficacy assessment, it is nevertheless important to make a distinction between causal inference of intended and unintended effects, in that the unknowns at stake are heterogonous in the two contexts. However, although “lower level” evidence is increasingly acknowledged to be a valid source of information contributory to assessing the risk profile of medications on theoretical or empirical grounds, current practices have difficulty in assigning a precise epistemic status to this kind of evidence because they are more or less implicitly parasitic on the (statistical) methods developed to test drug efficacy. My thesis is that (1) “lower level” evidence is justified on distinct grounds and at different conditions depending on the different epistemologies which one wishes to endorse, in that each impose different constraints on the methods we adopt to collect and evaluate evidence; (2) such constraints ought to be understood to be different in the case of evidence for risk versus benefit assessment for a series of reasons which I will illustrate on the basis of the recent debate on the causal association between acetaminophen (a.k.a. paracetamol) and asthma
Pharmaceutical risk communication: sources of uncertainty and legal tools of uncertainty management
Full text linkRisk communication has been generally categorized as a warning act, which is performed in order to prevent or minimize risk. On the other side, risk analysis has also underscored the role played by information in reducing uncertainty about risk. In both approaches the safety aspects related to the protection of the right to health are on focus. However, it seems that there are cases where a risk cannot possibly be avoided or uncertainty reduced, this is for instance valid for the declaration of side effects associated with pharmaceutical products or when a decision about drug approval or retirement must be delivered on the available evidence. In these cases, risk communication seems to accomplish other tasks than preventing risk or reducing uncertainty.
The present paper analyzes the legal instruments which have been developed in order to control and manage the risks related to drugs – such as the notion of “development risk” or “residual risk” – and relates them to different kinds of uncertainty. These are conceptualized as epistemic, ecological, metric, ethical, and stochastic, depending on their nature. By referring to this taxonomy, different functions of pharmaceutical risk communication are identified and connected with the legal tools of uncertainty management.
The purpose is to distinguish the different functions of risk communication and make explicit their different legal nature and implications
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