Born at Taurisano, Vanini studied philosophy in Rome. He studied law in Padua, where he was also ordained a priest. When around thirty years of age, he was accused of atheism, which, in order to clear his name, led him to France. He looks to have avoided prosecution by publishing Amphitheatrum Aeternae Providentiae Divino-Magicum (1615). A year later, however, he published De Admirandis Naturae Reginae Deaeque Mortalium Arcanis (1616), which resurrected the accusation of atheism. He was arrested in 1618, tried, and condemned to be burned at the stake. He was executed February 9, 1619, at Toulouse.

Vanini's work does not appear to have had any influence on Descartes’. Even so, Descartes mentions Vanini in private correspondence; for instance, in a letter to Isaac Beeckman (AT I 158, CSMK 27), and again in a letter to Gysbertus Voetius (AT VIIIB 175, CSMK 223). In the letter to Beeckman, Descartes appears to cast Vanini in a negative light, listing him among certain philosophers and “innovators,” a list on which Descartes refuses to be cast as a member. In the letter to Voetius, Descartes addresses the former's comparison of him to Vanini. As Descartes read Voetius, the comparison was supposed to suggest that his work, like Vanini's, could lead readers to atheism.

“Hyperaspistes” is the name of an anonymous critic of the Meditations. The word derives from the Greek word for “champion” or “defender” (CSMK 188 n. 1). In the collection of letters assembled by Clerselier (vol. 2), it is Letter XV that is from a man calling himself “Hyperaspistes.” A version of this letter is found in volume 3 of the Adam and Tannery collection (AT III 397–412). However, unlike Letter XV of the Clerselier collection, the Adam and Tannery letter does not explicitly identify Hyperaspistes as the author (although it is speculated in a footnote). Versions of Descartes’ reply are also included in both the Clerselier and the Adam and Tannery collections (AT III 422–35, CSMK 188–97). There appears to have been a precedent for the use of the pseudonym “Hyperaspistes.” It is found, for example, in the title of a book written by Johannes Kepler (1625), in which Kepler dubs himself “Hyperaspistes” or “defender” of Tycho Brahe.

Some have speculated that Hyperaspistes was a physician or perhaps a priest interested in philosophy, for in his objections to Descartes he mentions his encounter with a blind man among “our three hundred blind men living at Paris” (AT III 409). Some, including Baillet, believed this to be a reference to the Hôpital des Quinze-Vingts, a Paris almshouse for the blind. This and other clues led Baillet to speculate that Hyperaspistes was very likely a man by the name of M. Porlier (Agostini 2003, 8). Igor Agostini (2003, 7) argues against Baillet's conclusion. Other scholars have speculated that Hyperaspistes was a member of a group of natural philosophers associated with Pierre Gassendi, author of the Fifth Objections. In the Adam and Tannery collection, Hyperaspistes’ objections are made in a letter dated July 1641 (AT III 397–412). The letter is written in Latin and includes fourteen objections. Descartes expresses to Hyperaspistes the possibility of including the exchange in the first printing of the Meditations (AT III 422, CSMK 188). But their exchange did not make it into the final printing.

Descartes introduces the notion of material falsity in the Third Meditation. An idea is materially false, he says, whenever it represents a nonthing as a thing. He contrasts material falsity to another kind of falsity, namely, formal falsity, which, he says, “can occur only in judgments” (AT VII 43, CSM II 30). The difference, then, is that whereas material falsity has its origin in ideation (or in the faculty of representation), specifically in sensory ideas, formal falsity, in being related to judgment, has its origin in the will. To help clarify the notion, Descartes offers the example of the sensory idea of cold. Suppose that one is holding an ice cube in one's hand and that the sensory idea of this ice cube presents cold as a real and positive quality. “If it is true that cold is nothing but the absence of heat [i.e., cold is a privation; so it is nothing at all], the idea which represents it to me as something real and positive deserves to be called false” (AT VII 44; CSM II 30). This kind of falsity is present in the idea even before judgment, and because this is so, it could lead one to judge falsely that the ice cube is cold.

Several related interpretations of the notion of material falsity have emerged in the secondary literature. One interpretation emphasizes Descartes’ mention of a thing (res) in his discussion of the notion, which in this context scholars have interpreted as substance (Wilson 1978, Menn 1995). Here, an idea is said to be materially false whenever it represents something that is not a thing or substance as though it were a thing or substance. In the case of the idea of cold, then, the idea is taken to be materially false whenever it represents cold, which is a mode (or quality), as though it were a substance. A second interpretation emphasizes the conceptual or logical relation that holds between modes and their principal attributes (Field 1993). On this view, an idea is said to be materially false whenever it represents cold, for example, which strictly speaking is a mode of mind, as though it were a mode of body or extension (in terms of the example, it represents cold to be a mode of the ice cube). Here, the idea “represents” a conceptual or logical impossibility.

The concept of enumeration is introduced by Descartes within the context of his discussions on method, playing central roles in both the analysis and synthesis of ideas. The earliest and clearest discussion of the concept is found in the unpublished Rules for the Direction of the Mind (1628). The concept is also mentioned in his first published work, Discourse on Method (1637). A close examination of the concept of enumeration shows that it also plays an important role in his accounts of clarity and distinctness, which are important concepts in Cartesian epistemology.

Commentators have traditionally understood enumeration in its standard sense, namely, as the numbering or listing of items (Curley 1986). This may explain why the significance of the concept in Cartesian philosophy has been overlooked. When seen in connection with Descartes’ employment of common natures, the enumeration appears to be akin to a logical partition (Smith 2001, 2010). The elements of ideas are what Descartes calls in the Rules the “simple natures” (Marion 1999). So, an enumeration of ideas might be best understood as a partition of the simple natures.

We produce an enumeration of objects whenever we place each object of inquiry into exactly one class, where the union of the classes produced is the original set of objects with which we began. For example, suppose that we wish to produce an enumeration of a bunch of marbles on a table. We will produce an enumeration of the marbles if, and only if, we place each marble in exactly one jar (a jar in this case will be analogue to a class), where the union of (the contents of) the jars will be the original bunch of marbles on the table.

The sorting is accomplished by applying a specific kind of relation: an equivalence relation. Such relations are reflexive, symmetric, and transitive. For example, x is the same color as y is an equivalence relation. If those marbles on the table are monochromatic, applying this equivalence relation to the marbles will sort them – marbles of the same color will be placed in the same jar. So, if “A is the same color as B” is true, then marbles A and B are placed in the same jar.

Introduction

Energy is essential for human development and energy systems are a crucial entry point for addressing the most pressing global challenges of the 21st century, including sustainable economic and social development, poverty eradication, adequate food production and food security, health for all, climate protection, conservation of ecosystems, peace and security. Yet, more than a decade into the 21st century, current energy systems do not meet these challenges.

A major transformation is therefore required to address these challenges and to avoid potentially catastrophic future consequences for human and planetary systems. The Global Energy Assessment (GEA) demonstrates that energy system change is the key for addressing and resolving these challenges. The GEA identifies strategies that could help resolve the multiple challenges simultaneously and bring multiple benefits. Their successful implementation requires determined, sustained and immediate action.

Transformative change in the energy system may not be internally generated; due to institutional inertia, incumbency and lack of capacity and agility of existing organizations to respond effectively to changing conditions. In such situations clear and consistent external policy signals may be required to initiate and sustain the transformative change needed to meet the sustainability challenges of the 21st century.

The industrial revolution catapulted humanity onto an explosive development path, whereby, reliance on muscle power and traditional biomass was replaced mostly by fossil fuels. In 2005, some 78% of global energy was based on fossil energy sources that provided abundant and ever cheaper energy services to more than half the people in the world.

Introduction

Energy is essential for human development and energy systems are a crucial entry point for addressing the most pressing global challenges of the 21st century, including sustainable economic, and social development, poverty eradication, adequate food production and food security, health for all, climate protection, conservation of ecosystems, peace, and security. Yet, more than a decade into the 21st century, current energy systems do not meet these challenges.

In this context, two considerations are important. The first is the capacity and agility of the players within the energy system to seize opportunities in response to these challenges. The second is the response capacity of the energy system itself, as the investments are long-term and tend to follow standard financial patterns, mainly avoiding risks and price instabilities. This traditional approach does not embrace the transformation needed to respond properly to the economic, environmental, and social sustainability challenges of the 21st century.

A major transformation is required to address these challenges and to avoid potentially catastrophic consequences for human and planetary systems. The GEA identifies strategies that could help resolve the multiple challenges simultaneously and bring multiple benefits. Their successful implementation requires determined, sustained, and immediate action.

The industrial revolution catapulted humanity onto an explosive development path, whereby reliance on muscle power and traditional biomass was replaced mostly by fossil fuels. In 2005, approximately 78% of global energy was based on fossil energy sources that provided abundant and ever cheaper energy services to more than half the world's population.