This entry provides an overview of some key positions on God and time and discusses arguments for and against divine timelessness. The final section outlines some other philosophical contexts in which the concept of eternity can play a role.

The survival enhancing propensity (SEP) account has a crucial role to play in the analysis of proper function. However, a central feature of the account, its specification of the proper environment to which functions are relativized, is seriously underdeveloped. In this paper, I argue that existent accounts of proper environment fail because they either allow too many or too few characters to count as proper functions. While SEP accounts retain their promise, they are unworkable because of their inability to specify (...) this important feature. However, I suggest that this problem can be overcome by the application of a new strategy for specifying proper environment that is grounded in the operation of natural selection and I conclude by offering a first approximation of such an account. (shrink)

[From SEP]: Contemporary virtue epistemology (hereafter ‘VE’) is a diverse collection of approaches to epistemology. At least two central tendencies are discernible among the approaches. First, they view epistemology as a normative discipline. Second, they view intellectual agents and communities as the primary focus of epistemic evaluation, with a focus on the intellectual virtues and vices embodied in and expressed by these agents and communities. This entry introduces many of the most important results of the contemporary VE research program. These (...) include novel attempts to resolve longstanding disputes, solve perennial problems, grapple with novel challenges, and expand epistemology’s horizons. In the process, it reveals the diversity within VE. Beyond sharing the two unifying commitments mentioned above, its practitioners diverge over the nature of intellectual virtues, which questions to ask, and which methods to use. It will be helpful to note some terminology before proceeding. First, we use ‘cognitive’, ‘epistemic’ and ‘intellectual’ synonymously. Second, we often use ‘normative’ broadly to include not only norms and rules, but also duties and values. Finally, ‘practitioners’ names contemporary virtue epistemologists. (shrink)

There are many familiar theorems whose proofs use methods which are in some appropriate sense substantially more "abstract" than its statement. Some particularly well known examples come from the use of complex variables in number theory. Sometimes such abstraction can be removed - for example by the "elementary proof of the prime number theorem" - and sometimes no appropriate removal is known. The interest in removing abstraction typically varies, with no agreed upon criteria for appropriateness. E.g., the removal might sacrifice (...) naturalness or intelligibility, or the result of the removal criticized as being merely a thinly disguised form of the original. (shrink)

The role of animals in the realm of sport is the focus of this special issue which delves into the nuanced intersections of sport, animals, and ethics. For millennia, humans have forged multifacete...

Those are the words of Pope John Paul II, speaking in March 2004 to an international congress held in Rome. The conference was on "Life-sustaining Treatments and Vegetative State: Scientific Advances and Ethical Dilemmas," and it was organized by the World Federation of Catholic Medical Associations and the Pontifical Academy for Life. The pope was able to cut through all the ethical dilemmas. Although he acknowledged that a patient in a persistent vegetative state, or PVS, "shows no evident sign of (...) selfawareness or of awareness of the environment, and seems unable to interact with others or to react to specific stimuli," he said that they should be kept alive indefinitely. Such patients, he insisted, "retain their human dignity in all its fullness" and "the loving gaze of God the Father continues to fall upon them." For this reason, he said, it is obligatory to continue to provide them with food and water, even if this can only be done through a tube. The pope added that to withdraw the tube, knowing that it will lead to the death of the patient, is "euthanasia by omission.". (shrink)

Este artículo revisa los problemas relacionados con la distinción actual entre Ética pública y Ética privada; una distinción basada en una tesis reduccionista, según la cual los políticos y empleados públicos son los únicos sujetos agentes en los asuntos de Ética pública. El autor destaca especialmente que la noción actual de Ética Pública cae en el error de aislar en el espacio privado, cuestiones relacionadas con la Ética pública. Un concepto tan limitado, es un gran error que ha servido para (...) ocultar del foco de la Ética Pública una gran cantidad de asuntos vitales que van más allá del campo de interrelación público-privado. Los partidos políticos, los sindicatos, los contribuyentes, los contratistas, los medios de comunicación, las personas subsidiadas, los ciudadanos en general; todos ellos tienen un papel muy importante en la esfera pública, y por lo tanto son agentes en temas de Ética Pública. Por estas razones, el autor refuta la visión estrecha del concepto actual de Ética Pública y cree imprescindible repensarlo, objetiva y subjetivamente. Por otra parte, este estudio examina el nuevo panorama de los "códigos de ética" en España, con una mirada crítica cuando son sólo normas legales acompañadas de sanciones y no verdaderos “códigos de ética”. Estos principios, llamados "principios éticos", deberían ser deberes que los funcionarios públicos poseen por sí mismos y no por imposición. Por el contrario, en el caso que examinamos, esos principios son claramente deberes establecidos en la Constitución Española de 1978 y representan las obligaciones más primarias, superlativas y básicas de un empleado público. En un estado de duda moral, los códigos podrían ser útiles para proporcionar consejo, dando una regla para resolver el dilema ético. El autor reconoce que, en determinadas circunstancias, en tales casos, los códigos de ética pueden ayudar a los servidores públicos como guía en sus decisiones. Sin embargo, la obligación de respetar y garantizar el respeto de los mandatos constitucionales y la prohibición de la discriminación contra las personas por motivos de raza, sexo, religión.., u otras circunstancias, no plantean cuestiones morales. Por esa razón, el autor considera que el Estatuto Básico del Empleado Público en España comete un error al establecer como un principio ético, el deber de cumplir con la Constitución; el más alto deber legal que uno puede imaginar en el caso de los servidores públicos. (shrink)

Sustained peripheral somatosensory stimulations, such as high-frequency repetitive somatosensory stimulation (HF-RSS) and vibrated stimulation, are effective in altering the balance between excitation and inhibition in the somatosensory cortex (S1) and motor cortex (M1). A recent study reported that whole-hand water flow (WF) stimulation induced neural disinhibition in the M1. Based on previous results, we hypothesized that whole-hand WF stimulation would lead to neural disinhibition in the S1 because there is a strong neural connection between M1 and S1 and aimed to (...) examine whether whole-hand WF stimulation would change the neural balance between excitation and inhibition in the S1. Nineteen healthy volunteers were studied by measuring excitation and inhibition in the S1 before and after each of the four 15-min interventions. The excitation and inhibition in the S1 were assessed using somatosensory evoked potentials (SEPs) and paired-pulse inhibition (PPI) induced by single- and paired-pulse stimulations, respectively. The four interventions were as follows: control, whole-hand water immersion, whole-hand WF, and HF-RSS. The results showed no significant changes in SEPs and PPI following any intervention. However, changes in PPI with an interstimulus interval (ISI) of 30 ms were significantly correlated with the baseline value before whole-hand WF. Thus, the present findings indicated that the whole-hand WF stimulation had a greater decreased neural inhibition in participants with higher neural inhibition in the S1 at baseline. Considering previous results on M1, the present results possibly show that S1 has lower plasticity than M1 and that the duration (15 min) of each intervention may not have been enough to alter the balance of excitation and inhibition in the S1. (shrink)

Latest version of my SEP entry on ontological arguments, which first appeared in 1996. General discussion of ontological arguments. Includes a brief historical overview, a taxonomy of different kinds of ontological arguments, a brief survey of objections to the different kinds of ontological arguments identified in the taxonomy, and more extended discussions of Anselm's ontological argument (Proslogion 2), Godel's ontological argument, and Plantinga's ontological argument.

Sep 17 Time travel in Special Relativity (1) Nahin 1999: 439-51 & 459-66; (2) Taylor & Wheeler 1992: 121-35; (3) Nahin 1999: 343-8. Sep 24 Time travel in General Relativity (1) Malament 1985: 91-5; (2) Thorne 1994: 483-90 & 498-521; (3) Gott 2001: 92-110. Oct 1 Time travel in Quantum Mechanics (1) Albert 1992: 17-38, 73-9, & 112-5; (2) Barrett 1999: 149-62; (3) Deutsch & Lockwood 1994.

The Stanford Encyclopedia of Philosophy is an open access, dynamic reference work designed to organize professional philosophers so that they can write, edit, and maintain a reference work in philosophy that is responsive to new research. From its inception, the SEP was designed so that each entry is maintained and kept up to date by an expert or group of experts in the field. All entries and substantive updates are refereed by the members of a distinguished Editorial Board before they (...) are made public. (shrink)

Translation into Portuguese of SEP entries on Philosophy of Economics.

There is a strong philosophical intuition that direct study of the brain can and will constrain the development of psychological theory. When this intuition is tested against case studies on the neurophysiology and psychology of perception and memory, it turns out that psychology has led the way toward knowledge of neurophysiology. An abstract argument is developed to show that psychology can and must lead the way in neuroscientific study of mental function. The opposing intuition is based on mainly weak arguments (...) about the fundamentality or objectivity of physics or physiology in relation to psychology. -/- Philosophy of Science, Vol. 67, Supplement. Proceedings of the 1998 Biennial Meetings of the Philosophy of Science Association. Part II: Symposia Papers (Sep., 2000). (shrink)

Philosophy of Science, Volume 63, Issue Supplement. Proceedings of the 1996 Biennial Meetings of the Philosophy of Science Association. Part I: Contributed Papers (Sep.

entry for the Stanford Encyclopedia of Philosophy (SEP) This entry will attempt to provide a broad overview of the central themes of Leibniz’s philosophy of physics, as well as an introduction to some of the principal arguments and argumentative strategies he used to defend his positions. It tentatively includes sections entitled, The Historical Development of Leibniz’s Physics, Leibniz on Matter, Leibniz’s Dynamics, Leibniz on the Laws of Motion, Leibniz on Space and Time. A bibliography arranged by topic is also included. (...) A working draft is available here (comments, as always welcome): draft. (shrink)

Lucas Matthews and I substantially revised my SEP entry on Heritability. This version includes discussion of the missing heritability problem and other issues that arise from the use of Genome Wide Association Studies by Behavioral Geneticists.

Actualists routinely characterize their view by means of the slogan, “Everything is actual.” They say that there aren’t any things that exist but do not actually exist—there aren’t any “mere possibilia.” If there are any things that deserve the label ‘possible world’, they are just actually existing entities of some kind—maximally consistent sets of sentences, or maximal uninstantiated properties, or maximal possible states of affairs, or something along those lines. Possibilists, in contrast, do think that there are mere possibilia, that (...) there are things that are not actual. They think that more exists than what actually exists. All I have done so far, though, is rephrase the slogan in various ways. To say that everything is actual is precisely to say that there are no things that do not actually exist, which is precisely to say that there are no mere possibilia, and which is also precisely to say that we cannot sep- arately quantify over what exists and what is actual. These claims all amount to the same thing. But what is that, exactly? What on earth does it mean to say that everything is actual, that there are no mere possibilia, and so on? What does the actualist slogan really come to? I think the literature is far from clear on this point, and that people work themselves into unnecessary muddles because of it. Indeed, certain confusions that I shall discuss in the first half of this article seem to be on the rise. It is high time to lay out the issues and the choice points as clearly as possible. There are two primary choices to be made; there are two axes along which versions of actualism can vary. One choice has to do with how to treat claims about things that merely could exist. The other choice has to do with the modal status of the view and of how we should think about the “actual” in actualism. I make no claim that the positions I will eventually endorse are star- tlingly new. I think that most people will agree with the decisions I make at both choice points and will in fact find some bits of this essay obvious. But not everyone agrees with my decisions, and it has been my experience that people differ remarkably about which bits they find obvious—a fact I find rather telling. My goal, then, is to show that the two axes are there and to clarify the consequences of the choices. (shrink)

The current IASP definition of pain has come under renewed criticisms recently. There is a new momentum for its revision as reflected by the fact that IASP has now a Presidential Task Force dedicated to look into whether there is enough warrant to update the definition. I critically review all the major criticisms of the current definition in detail, and raise new difficulties rarely discussed before. I show that none of the major criticisms has enough warrant to force us to (...) substantially revise the current definition. Combined with the discussion of the new difficulties, there is nonetheless a need to restate the definition using slightly different terminology that will make the original intent of the current definition clearer and more precise. A restatement of the definition is proposed and its potential is discussed in light of some empirical questions that remain. [The IASP Council has now approved a revised definition and published its rationale here: Pain 2020 Sep 1; 161(9), pp. 1976–1982. The new definition follows (most of) my recommendations.]. (shrink)

An encyclopedia article on the epistemic or knowledge condition for moral responsibility, written for the SEP.

General discussion of ontological arguments. (Extended the discussion of ontological arguments in the then current version of my SEP entry on ontological arguments.).

The translation of this work has been funded by SEPS - Segretariato Europeo per le Pubblicazioni Scientifiche.

El artículo aborda el antagonismo jurídico entre la acción de lesividad y su procedencia frente a actos administrativos regulares e irregulares en Ecuador, enfocándose en la tensión entre las resoluciones de la Corte Constitucional y la Corte Nacional. El problema radica en la aplicación de la acción de lesividad, especialmente en casos donde los actos administrativos presentan vicios de legalidad como fue el caso de la sentencia No. 030-18-SEP-CC. El objetivo es analizar las discrepancias jurisprudenciales y sus implicaciones en la (...) seguridad jurídica a través del principio de legalidad. El método utilizado es no experimental y explicativo, con un enfoque cualitativo basado en análisis documental y bibliográfico. Se examina la validez de los actos administrativos, los fundamentos doctrinales e históricos de la acción de lesividad, y la legislación comparada. Los hallazgos indican una falta de consenso entre las Cortes sobre la aplicabilidad de la acción de lesividad en actos administrativos irregulares. Mientras la Corte Constitucional favorece la seguridad jurídica del administrado, al permitir la acción de lesividad incluso en actos irregulares, la Corte Nacional sostiene que solo debe aplicarse en actos regulares o con vicios convalidables. Las conclusiones destacan la importancia de una interpretación coherente y uniforme de la ley para garantizar la seguridad jurídica. Esta investigación contribuye al entendimiento del derecho administrativo en Ecuador, ofreciendo una perspectiva crítica sobre la coexistencia de reglas jurisprudenciales y la práctica administrativa. (shrink)

We determine the computational complexity of the Hahn-Banach Extension Theorem. To do so, we investigate some basic connections between reverse mathematics and computable analysis. In particular, we use Weak König's Lemma within the framework of computable analysis to classify incomputable functions of low complexity. By defining the multivalued function Sep and a natural notion of reducibility for multivalued functions, we obtain a computational counterpart of the subsystem of second-order arithmetic WKL0. We study analogies and differences between WKL0 and the class (...) of Sep-computable multivalued functions. Extending work of Brattka, we show that a natural multivalued function associated with the Hahn-Banach Extension Theorem is Sep-complete. (shrink)

**No longer the current version available on SEP; see revised version by Sharon Crasnow** -/- Feminists have a number of distinct interests in, and perspectives on, science. The tools of science have been a crucial resource for understanding the nature, impact, and prospects for changing gender-based forms of oppression; in this spirit, feminists actively draw on, and contribute to, the research programs of a wide range of sciences. At the same time, feminists have identified the sciences as a source as (...) well as a locus of gender inequalities: the institutions of science have a long tradition of excluding women as practitioners; feminist critics of science find that women and gender (or, more broadly, issues of concern to women and sex/gender minorities) are routinely marginalized as subjects of scientific inquiry, or are treated in ways that reproduce gender-normative stereotypes; and, closing the circle, scientific authority has frequently served to rationalize the kinds of social roles and institutions that feminists call into question. -/- Feminist perspectives on science therefore reflect a broad spectrum of epistemic attitudes toward and appraisals of science. Some urge the reform of gender inequities in the institutions of science and call for attention to neglected questions with the aim of improving the sciences in their own terms; they do not challenge the standards and practices of the sciences they engage. Others pursue jointly critical and constructive programs of research that, to varying degrees, aim at transforming the methodologies, substantive content, framework assumptions, and epistemic ideals that animate the sciences. The content of these perspectives, and the degree to which they generate transformative critique, depends not only on the types of philosophical and political commitments that inform them but also on the nature of the sciences and subject domains on which they bear. Feminist perspectives have had greatest impact on sciences that deal with inherently gendered subjects—the social and human sciences—and, secondarily, on sciences that study subjects characterized in gendered terms, metaphorically or by analogy (projectively gendered subjects), chiefly the biological and life sciences. Feminist perspectives are relevant to sciences that deal with non-gendered subject matters, but perspectives vary substantially in content and in critical import depending on the sciences and the particular research programs they engage. (shrink)

Objective: The COVID-19 epidemic has generated great stress throughout healthcare workers. The situation of HCWs should be fully and timely understood. The aim of this meta-analysis is to determine the psychological impact of COVID-19 pandemic on health care workers.Method: We searched the original literatures published from 1 Nov 2019 to 20 Sep 2020 in electronic databases of PUBMED, EMBASE and WEB OF SCIENCE. Forty-seven studies were included in the meta-analysis with a combined total of 81,277 participants.Results: The pooled prevalence of (...) anxiety is 37% from 44 studies. Depression is estimated in 39 studies, and the pooled prevalence of depression is 36%. There are 10 studies reported the prevalence of insomnia, and the overall prevalence of insomnia is 32%. The subgroup analysis showed a higher incidence of anxiety and depression among women and the frontline HCWs compared to men and non-frontline HCWs respectively.Conclusions: The COVID-19 pandemic has caused heavy psychological impact among healthcare professionals especially women and frontline workers. Timely psychological counseling and intervention ought to be implemented for HCWs in order to alleviate their anxiety and improve their general mental health. (shrink)

There are two curious features about the backward induction argument (BIA) to the effect that repeated non-cooperation is the rational solution to the finite iterated prisoner’s dilemma (FIPD). First, however compelling the argument may seem, one remains hesitant either to recommend this solu- tion to players who are about to engage in cooperation or to explain cooperation as a deviation from rational play in real-life FIPD’s. Second, there seems to be a similarity between the BIA for the FIPD and the (...) surprise exam paradox (SEP) and one cannot help but wonder whether the former is indeed no more than an instance of the latter. I argue that there is an important difference between the BIA for the FIPD and the SEP, but that a comparison to the SEP can help us understand why the conclusion of the BIA for the FIPD strikes us as a counterintuitive solution to real-life FIPD’s. (shrink)

Spinoza studies have seen a renaissance of interest in his views on modality, from which considerable disagreement has emerged about Spinoza's modal commitments. Much of this disagreement stems from larger interpretive disagreements about Spinoza's metaphysics. After a brief introduction, this SEP article begins with Spinoza's views on the distribution of modal properties, which quickly leads the heart of Spinoza's metaphysics, intersecting his views on causation, inherence, God, ontological plenitude and the principle of sufficient reason. Although the question of whether Spinoza (...) was a necessitarian is the predominant topic of discussion in the recent secondary literature on Spinoza's modal views, Spinoza also sketches interesting accounts of the nature of modality and the ground of modality that shed fresh light on his modal commitments. Though understudied by recent interpreters, these latter topics were of interest to Spinoza's peers and remain vibrant research questions in contemporary metaphysics of modality. (shrink)

Firms have traditionally responded to environmental violations by increasing information disclosure and/or communication to manage stakeholder perceptions. As such, these approaches may be symbolic in nature, with no genuine intention to improve the environment. We draw from restorative justice grounded in stakeholder theory and explore a relatively new approach in the form of supplemental environmental projects aimed at restoring the environment, and empirically examine the role of corporate governance in firms’ decisions to undertake reparative actions. Using environmental violations and SEPs (...) data from the US Environmental Protection Agency between 2002 and 2015, we find that firms with smaller boards are more likely to undertake SEPs. We also find that firms with higher board independence and CEO duality undertake SEPs more frequently; however, board gender diversity and the existence of a sustainability committee appear to have no impacts. These results are robust to propensity score matching and an alternative data source. We extend the scope of stakeholder theory by emphasizing a new approach—restorative justice—by which corporations can repair damaged relationships and also improve the environment. We also contribute to corporate governance and environmentalism literature by identifying governance structures that promote environmental restorative justice. Thus, our study will inform different stakeholders, including regulators, shareholders, and boards of directors, and will open new avenues for business ethics scholarship. (shrink)

Notice: This PDF version was distributed by request to members of the Friends of the SEP Society and by courtesy to SEP content contributors. It is solely for their fair use. Unauthorized distribution is prohibited. To learn how to join the Friends of the..

An important question in the business ethics literature concerns organizational response in the aftermath of an unethical business practice. This study examines factors affecting firms’ decision to take reparative action in the aftermath of an environmental violation. Specifically, we investigate environmental violators’ decision to undertake a Supplemental Environmental Project (SEP), which is an initiative that promotes restorative justice. To settle an environmental violation, the United States’ environmental regulator allows offenders the option of either paying the full penalty or a reduced (...) sum while spending additional effort and engaging in an environmental project. As predicted, we find that firms with poorer past environmental performance and greater shareholder environmental activism are more likely to engage and invest in a SEP. Additionally, there is a stronger association between shareholder activism and SEP investment when firms have poorer past environmental performance. Our findings inform regulators, stakeholders, and business ethics researchers on the factors that lead firms to undertake reparative action following unethical business practices. (shrink)

In 1995, as a student of psychology inspired by natural science, I defined a logical model of personality explaining psychosis. I created (for my MA thesis, 1998 and grant research, 1999) new kind of tests assessing intelligence, creativity, prejudices, expectations to show more exact methods in psychology. During my Phd study in economics, I developed 'Maximization of Uniqueness (Originality)' model enhancing the classic utility to explain irrational motivations linking economics and psychology. Later I became computer programmer developing functional programming. According (...) to Personality model (and my experience in chess composition), I've built server and client logic of information system www.each.co.uk, and produced visual art. I presented the excerpts of 'Personality Model' in a few articles, and later as part of my art exhibitions: From Animation (Oct 2013, Holland Park, London), Parallax 12 (Feb 2015, Chelsea Town Hall, London), Fading Memory (Sep 2015, Weißenohe / Nuremberg, Germany). Another work: The Science is a subset of the Art extends Personality Model to art, society. At the end I add example and explanation of a special problem, when the higher intelligence leads to a wrong solution. It was published in Japanese Journal Problem Paradise in 1999. All presented results can be repeated. Computer testing would enable to acquire more data and more exact analysis. (shrink)

Notice: This PDF version was distributed by request to members of the Friends of the SEP Society and by courtesy to SEP content contributors. It is solely for their fair use. Unauthorized distribution is prohibited. To learn how to join the Friends of the SEP Society and obtain authorized PDF versions of SEP entries, please visit https://leibniz.stanford.edu/friends/.

In this paper we study the logical strength of the determinacy of infinite binary games in terms of second order arithmetic. We define new determinacy schemata inspired by the Wadge classes of Polish spaces and show the following equivalences over the system RCA0*, which consists of the axioms of discrete ordered semi‐rings with exponentiation, Δ10 comprehension and Π00 induction, and which is known as a weaker system than the popularbase theory RCA0: 1. Bisep(Δ10, Σ10)‐Det* ↔ WKL0, 2. Bisep(Δ10, Σ20)‐Det* ↔ (...) ATR0 + Σ11 induction, 3. Bisep(Σ10, Σ20)‐Det* ↔ Sep(Σ10, Σ20)‐Det* ↔ Π11‐CA0, 4. Bisep(Δ20, Σ20)‐Det* ↔ Π11‐TR0, where Det* stands for the determinacy of infinite games in the Cantor space (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim). (shrink)

Endogenous and exogenous processes of attention have been inferred with different types of precues used in allocation of attention to a target location. In the present research, a comparison was made between the typical peripheral single-element precue (SEP), a central precue, and a multiple-element precue (MEP) in order to further understanding of the processes involved in allocation of attention. Two precues were used on each trial in these experiments. An abrupt-onset precue appeared with an SEP, an MEP, or a central (...) precue and was followed 50 or 300 ms later by a screen containing a target and two distractor characters. The abrupt-onset precue and the other precue each could be valid or invalid in indicating the location of the target, as in the study by Juola, Koshino, and Warner (1995). Response times to the targets showed that validity effects of the abrupt-onset precue and the MEP or central precue were additive, whereas those of the abrupt-onset precue and the SEP were interactive. These data suggest that, like a central precue, an MEP is an endogenous precue that guides conscious control of attention and has its attentional effects at a different processing level from an SEP, which is an exogenous precue and may compete for attentional resources with an abrupt-onset precue. (shrink)

In people with chronic low back pain, maladaptive structural and functional changes on a cortical level have been identified. On a functional level, somatosensory cortical excitability has been shown to be reduced in chronic pain conditions, resulting in cortical disinhibition. The occurrence of structural and/or functional maladaptive cortical changes in people with CLBP could play a role in maintaining the pain. There is currently no measurement protocol for cortical excitability that employs stimulation directly to the lower back. We developed a (...) protocol for the measurement of single pulse somatosensory evoked potential waveforms and paired-pulse behavior generated from sensory nerves of the lower back and quantified its test–retest reliability in a sample of 30 healthy individuals to gain insights into the normal variability of cortical responses, which could then be compared to results from people with CLBP. We investigated cortical excitability by measuring SEPs and PPB. PPB was defined as the ratio of the amplitude of the second cortical response divided by the first cortical response. A2s was determined by subtracting the response to single-pulse stimuli from the paired pulse stimuli response to account for linear superposition effects. The test–retest reliability of the protocol was very poor with no evidence of systematic bias but a high amount of random variability between sessions. There was no significant difference in the right side PPB for session 1 and session 2 ; mean session difference [ = −0.44 ; t = −1.17, p = 0.26]. The ICC3.1 for the outlier-removed right side PPB were 0.19 and 0.43 for left side PPB. This finding potentially has wider implications for PPB protocols. If these findings were replicated in other groups and other nerves, it would question the validity of this measure more generally. However, these findings are restricted to healthy people and sensory nerves of the lower back and may not be generalizable. (shrink)