The provided text from the Stanford Encyclopedia of Philosophy explores the identity theory of truth, a philosophical position that contrasts with correspondence theories. Instead of asserting that truth-bearers are made true by facts, the identity theory proposes that at least some truth-bearers are identical to facts. The entry discusses the theory's definition, historical background, and motivations, as well as difficulties and possible solutions. It examines different versions of the theory, considering whether declarative sentences express Fregean thoughts, Russellian propositions, or both. The text further addresses problems such as modal concerns, the "right fact" problem, and congruence issues, offering potential resolutions and discussing intrinsicism. Ultimately, the entry provides a comprehensive overview of the identity theory and its implications for metaphysics, language, and mind.

The manifest appearance of function and purpose in living systems is responsible for the prevalence of apparently teleological explanations of organismic structure and behavior in biology. Although the attribution of function and purpose to living systems is an ancient practice, teleological notions are largely considered ineliminable from modern biological sciences, such as evolutionary biology, genetics, medicine, ethology, and psychiatry, because they play an important explanatory role.

Historical and recent examples of teleological claims include the following:

The chief function of the heart is the transmission and pumping of the blood through the arteries to the extremities of the body. (Harvey 1616 [1928: 49])

The Predator Detection hypothesis remains the strongest candidate for the function of stotting [by gazelles]. (Caro 1986: 663)

The geographic range of human malaria is much wider than the range of the sickle-cell gene. As it happens, other antimalarial genes take over the protective function of the sickle-cell gene in … other warm parts. (Diamond 1994: 83)

Despite the substantial amount of data we now have on theropod dinosaurs, more information is necessary in order to determine the likelihood that early feathers served an adaptive function in visual display as opposed to other proposed adaptive functions such as thermoregulation. (Dimond et al. 2011: 62)

The ubiquity of claims such as these raises the question: how should apparently teleological notions in biology be understood?

Most post-Darwinian approaches attempt to naturalize teleology in biology, in opposition to nineteenth-century viewpoints which grounded it theologically. Nevertheless, biologists and philosophers have continued to question the legitimacy of teleological notions in biology. For instance, Ernst Mayr (1988), identified four reasons why teleological notions remain controversial in biology, namely that they are:

1. vitalistic (positing some special ‘life-force’);
2. requiring backwards causation (because goal-directed explanations seem to use future outcomes to explain present traits);
3. incompatible with mechanistic explanation (because of 1 and 2);
4. mentalistic (attributing the action of mind where there is none).

A fifth complaint is that they are not empirically testable (Allen & Bekoff 1995). The current philosophical literature offers both Darwinian and non-Darwinian accounts of teleology in biology that aim to avoid these concerns. In this article, we hope to bring some clarity to the contemporary debates over the role of teleological notions in biology by sketching a taxonomy of the various accounts of biological function on offer (see Allen & Bekoff 1995 for a more comprehensive taxonomy that forms the basis of this presentation). We primarily focus on naturalistic accounts of biological function, since this is where we see the most lively and productive current debates (see, e.g., Garson 2016 for an extended survey). We also briefly discuss the notion of goal-directedness in section 2.

The idea of the social contract goes back at least to Protagoras and Epicurus. In its recognizably modern form, however, the idea is revived by Thomas Hobbes and was later developed, in different ways, by John Locke, Jean-Jacques Rousseau, and Immanuel Kant. After Kant, the idea fell out of favor with political philosophers until it was resurrected by John Rawls. It is now at the heart of the work of a number of moral and political philosophers.

The basic idea seems simple: in some way, the agreement of all individuals subject to collectively enforced social arrangements shows that those arrangements have some normative property (they are legitimate, just, obligating, etc.). Even this basic idea, though, is anything but simple, and even this abstract rendering is objectionable in many ways.

Political theorists propose standards that identify legitimate uses of political power. Some adopt a principle of public justification. A public justification is a kind of rationale for exercising power and control. It is public because the rationale, or group of rationales, is one that members of the public can accept. Put another way, to treat people as equals, we must ensure that political power is justified for or to them by their own lights, so a public justification thus consists of reasons the public can recognize as valid. Those who adopt a public justification standard are often called public reason liberals. Liberal institutions (freedom of speech, the rule of law, democracy) are publicly justified, but illiberal institutions are not. Diverse perspectives within the public will reject non-liberal institutions.

Coercion is the standard object of public justification because it is perhaps the characteristic feature of political life. Charles Larmore remarks that public justification has “to do with the sort of respect we owe one another in the political realm — that is, in relationships where the possibility of coercion is involved” (Larmore 2008, 86). John Rawls’s principle of public justification holds that political power requires justification (Rawls 2005, 12) because “political power is always coercive power” (Rawls 2005, 68). Jonathan Quong holds that public justification concerns the imposition of coercive laws (Quong 2011, 233–250). And, as Christopher Eberle puts it (2002, 54), “the clarion call of justificatory liberalism is the public justification of coercion.” Some have wondered whether non-coercive state actions need public justification (2.7). But they nonetheless agree that coercion generally, if not always, requires it.

The idea of a public justification is, at its root, an idea about which reasons justify coercion. Public justification is not a process of exchanging reasons. Instead, the exchange of reasons can uncover or generate a public justification. Or we could arrive at a public justification through a non-deliberative route. Examples include bargaining processes and adjudicative procedures. In this way, the ideas of public reason and public justification are distinct. Public justifications might consist of public reasons. But a reason shared by the public might fall short of a sound justification if other reasons undercut or override it. One might, for example, support a new anti-poverty program on shared grounds of justice for the poor. However, alternative programs reduce poverty more effectively. The original poverty program could be publicly justified based on a shared commitment to justice, but other shared reasons, like policy efficacy, can undercut the public justification for the program.

Rawls was the foremost advocate of the idea of public justification. But we find the idea stressed in the works of Jürgen Habermas, David Gauthier, Gerald Gaus, Stephen Macedo, Charles Larmore, Seyla Benhabib, and many others.

There is considerable disagreement about how to understand the idea. Some theorists hold that all public justifications consist of shared or accessible reasons. These are often called consensus theorists. Others allow diverse, unshared reasons to figure into public justifications. These are often called convergence theorists. (See Section 2.3 below). Public justification theorists also disagree about how to attribute reasons to citizens. This disagreement is about the right level of idealization. Idealization involves modeling someone as having improved information and cognitive capacities. The goal is to identify which reasons apply to her, even if she cannot or will not see them as such in her ordinary life. Some theorists adopt more radical idealizations than others.

This entry addresses disputes about public justification by articulating an open-ended principle. This Public Justification Principle (PJP) helps classify competing conceptions of public justification.

The original position is a central feature of John Rawls’s social contract account of justice, “justice as fairness,” set forth in A Theory of Justice (TJ). The original position is designed to be a fair and impartial point of view that is to be adopted in our reasoning about fundamental principles of justice. In taking up this point of view, we are to imagine ourselves in the position of free and equal persons who jointly agree upon and commit themselves to principles of social and political justice for a well-ordered democratic society. The main distinguishing feature of the original position is “the veil of ignorance”: To ensure complete impartiality of judgment, the parties are deprived of all knowledge of their personal characteristics and conceptions of the good, and of social and historical circumstances. They do know of certain fundamental interests they all have in exercising their moral powers, plus general facts about psychology, economics, political sociology, biology, and other social and natural sciences. The parties in the original position are presented with a list of the major conceptions of justice drawn from the tradition of social and political philosophy and are assigned the task of choosing from among these the conception of justice that best enables them to effectively pursue their final ends and commitments and their fundamental interests. Rawls contends that the most rational decision for the parties in the original position are the two principles of justice: The first principle guarantees the equal basic rights and liberties needed to secure the fundamental interests of free and equal citizens and to pursue a wide range of conceptions of the good. The basic liberties include freedom of conscience, thought, expression, and association; freedom and integrity of the person with the right to hold personal property; equal political liberties, and rights protected by the rule of law. The second principle regulates permissible social and economic inequalities: first it provides fair equality of educational, employment, and cultural opportunities that enable all to develop their capacities and fairly compete for social positions of office and responsibility. Next, the second principle requires economic inequalities of income, wealth, powers and prerogatives to be arranged to maximally benefit the least advantaged members of society, making them better off than they would be in any alternative economic system (the difference principle.)

This entry from the Stanford Encyclopedia of Philosophy explores ontological arguments, which attempt to prove God's existence through reason alone, rather than empirical observation. It traces the history of these arguments, beginning with Anselm of Canterbury, and including thinkers like Descartes, Leibniz, Gödel, and Plantinga. The text presents a taxonomy of different types of ontological arguments, such as definitional, conceptual, and modal arguments. It considers common criticisms, including Kant's claim that existence is not a predicate. It also examines the goals and potential uses of ontological arguments, along with parodies of them, such as Gaunilo's "perfect island" objection, and includes a discussion of specific arguments and their limitations. The entry ultimately suggests that while current ontological arguments may not persuade non-theists, the possibility of undiscovered, successful arguments remains an open question. The article also gives a short explanation of major philosophers that have contributed to this argument, and offers resources for further study.

The Stanford Encyclopedia of Philosophy entry on "Animal Consciousness" explores the complex intersection of scientific and philosophical perspectives on whether non-human animals possess consciousness. It examines the motivations for studying animal consciousness, ranging from understanding humanity's place in nature to the moral implications of animal treatment. The entry considers various concepts of consciousness, including phenomenal consciousness and self-consciousness, while also tracing the historical backdrop of this debate from ancient philosophy to modern science. It grapples with epistemological and metaphysical challenges in determining if and what animals experience. Finally, the entry analyzes different theories and their implications for the evolution and distribution of consciousness across the animal kingdom, while addressing special areas of study including animal pain and suffering, emotions, and self-awareness. It concludes that even with all these advances, much is still left to investigate in the field.

This text, excerpted from the Stanford Encyclopedia of Philosophy, provides an overview of Charles Sanders Peirce's extensive work in deductive logic. It highlights Peirce's expansion of logic in three dimensions: formalism, systems, and semantic values. The entry explores Peirce's contributions to predicate logic, diagrammatic systems (Existential Graphs), and three-valued logic. It also contextualizes Peirce's work within the broader history of logic, comparing him to contemporaries like Frege and examining his influence on subsequent logicians. The article presents Peirce’s motivations and explores how his pragmatic maxim shaped his innovative approaches to logical representation.