Oil and gas reserves and resource quantification

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Oil_and_gas_reserves_and_resource_quantification

Flaring a flow test, the first outward indication of a new oil or gas discovery, which has the potential to qualify for reserves assessment

Oil and gas reserves denote discovered quantities of crude oil and natural gas (oil or gas fields) that can be profitably produced/recovered from an approved development. Oil and gas reserves tied to approved operational plans filed on the day of reserves reporting are also sensitive to fluctuating global market pricing. The remaining resource estimates (after the reserves have been accounted) are likely sub-commercial and may still be under appraisal with the potential to be technically recoverable once commercially established. Natural gas is frequently associated with oil directly and gas reserves are commonly quoted in barrels of oil equivalent (BOE). Consequently, both oil and gas reserves, as well as resource estimates, follow the same reporting guidelines, and are referred to collectively hereinafter as oil & gas.

Quantification

An oil well in Canada

As with other mineral resource estimation, detailed classification schemes have been devised by industry specialists to quantify volumes of oil and gas accumulated underground (known as subsurface). These schemes provide management and investors with the means to make quantitative and relative comparisons between assets, before underwriting the significant cost of exploring for, developing and extracting those accumulations. Classification schemes are used to categorize the uncertainty in volume estimates of the recoverable oil and gas and the chance that they exist in reality (or risk that they do not) depending on the resource maturity. Potential subsurface oil and gas accumulations identified during exploration are classified and reported as prospective resources. Resources are re-classified as reserves following appraisal, at the point when a sufficient accumulation of commercial oil and/or gas are proven by drilling, with authorized and funded development plans to begin production within a recommended five years.

Reserve estimates are required by authorities and companies, and are primarily made to support operational or investment decision-making by companies or organisations involved in the business of developing and producing oil and gas. Reserve volumes are necessary to determine the financial status of the company, which may be obliged to report those estimates to shareholders and "resource holders" at the various stages of resource maturation.

Currently, the most widely accepted classification and reporting methodology is the 2018 petroleum resources management system (PRMS), which summarizes a consistent approach to estimating oil and gas quantities within a comprehensive classification framework, jointly developed by the Society of Petroleum Engineers (SPE), the World Petroleum Council (WPC), the American Association of Petroleum Geologists (AAPG), the Society of Petroleum Evaluation Engineers (SPEE) and the Society of Economic Geologists (SEG). Public companies that register securities in the U.S. market must report proved reserves under the Securities and Exchange Commission (SEC) reporting requirements which shares many elements with PRMS. Attempts have also been made to standardize more generalized methodologies for the reporting of national or basin level oil and gas resource assessments.

Reserves and resource reporting

An oil or gas resource refers to known (discovered fields) or potential accumulations of oil and/or gas (i.e undiscovered prospects and leads) in the subsurface of the Earth's crust. All reserve and resource estimates involve uncertainty in volume estimates (expressed below as Low, Mid or High uncertainty), as well as a risk or chance to exist in reality, depending on the level of appraisal or resource maturity that governs the amount of reliable geologic and engineering data available and the interpretation of those data.

TABLE I:Classification summary featuring volumes uncertainty (low, mid or high) with increasing chance for an accumulation to exist and be commercial upwards reflecting greater resource maturity

RESOURCE CLASS	LOW	MID	HIGH
Reserves	1P	2P	3P
Contingent Resources	1C	2C	3C
Prospective Resources	1U	2U	3U

Estimating and monitoring of reserves provides an insight into, for example, a company's future production and a country's oil & gas supply potential. As such, reserves are an important means of expressing value and longevity of resources.

In the PRMS, the terms 'Resources' and 'Reserves' have distinct and specific meaning with respect to oil & gas accumulations and hydrocarbon exploration in general. However, the level of rigor required in applying these terms varies depending on the resource maturity which informs reporting requirements. Oil & gas reserves are resources that are, or are reasonably certain to be, commercial (i.e. profitable). Reserves are the main asset of an oil & gas company; booking is the process by which they are added to the balance sheet. Contingent and prospective resource estimates are much more speculative and are not booked with the same degree of rigor, generally for internal company use only, reflecting a more limited data set and assessment maturity. If published externally, these volumes add to the perception of asset value, which in turn can influence oil & gas company share or stock value. The PRMS provides a framework for a consistent approach to the estimation process to comply with reporting requirements of particularly, listed companies. Energy companies may employ specialist, independent, reserve valuation consultants to provide third party reports as part of SEC filings for either reserves or resource booking.

Reserves

Reserves reporting of discovered accumulations is regulated by tight controls for informed investment decisions to quantify differing degrees of uncertainty in recoverable volumes. Reserves are defined in three sub-categories according to the system used in the PRMS: Proven (1P), Probable and Possible. Reserves defined as Probable and Possible are incremental (or additional) discovered volumes based on geological and/or engineering criteria similar to those used in estimating Proven reserves. Though not classified as contingent, some technical, contractual, or regulatory uncertainties preclude such reserves being classified as Proven. The most accepted definitions of these are based on those originally approved by the SPE and the WPC in 1997, requiring that reserves are discovered, recoverable, commercial and remaining based on rules governing the classification into sub-categories and the declared development project plans applied. Probable and Possible reserves may be used internally by oil companies and government agencies for future planning purposes but are not routinely or uniformly compiled.

Proven reserves

Main article: Proven reserves

Proven reserves are discovered volumes claimed to have a reasonable certainty of being recoverable under existing economic and political conditions, and with existing technology. Industry specialists refer to this category as "P90" (that is, having a 90% certainty of producing or exceeding the P90 volume on the probability distribution). Proven reserves are also known in the industry as 1P.  Proven reserves may be referred to as proven developed (PD) or as proven undeveloped (PUD). PD reserves are reserves that can be produced with existing wells and perforations, or from additional reservoirs where minimal additional investment (operating expense) is required (e.g. opening a set of perforations already installed). PUD reserves require additional capital investment (e.g., drilling new wells) to bring the oil and/or gas to the surface.

Accounting for production is an important exercise for businesses. Produced oil or gas that has been brought to surface (production) and sold on international markets or refined in-country are no longer reserves and are removed from the booking and company balance sheets. Until January 2010, "1P" proven reserves were the only type the U.S. SEC allowed oil companies to report to investors. Companies listed on U.S. stock exchanges may be called upon to verify their claims confidentially, but many governments and national oil companies do not disclose verifying data publicly. Since January 2010 the SEC now allows companies to also provide additional optional information declaring 2P (both proven and probable) and 3P (proven plus probable plus possible) with discretionary verification by qualified third party consultants, though many companies choose to use 2P and 3P estimates only for internal purposes.

Probable and possible reserves

An example of a Volume Uncertainty Distribution, with the P10, P50 and P90 volumes indicated (created using a probabilistic calculation method)

Probable additional reserves are attributed to known accumulations and the probabilistic, cumulative sum of proven and probable reserves (with a probability of P50), also referred to in the industry as "2P" (Proven plus Probable) The P50 designation means that there should be at least a 50% chance that the actual volumes recovered will be equal to or will exceed the 2P estimate.

Possible additional reserves are attributed to known accumulations that have a lower chance of being recovered than probable reserves. Reasons for assigning a lower probability to recovering Possible reserves include varying interpretations of geology, uncertainty due to reserve infill (associated with variability in seepage towards a production well from adjacent areas) and projected reserves based on future recovery methods. The probabilistic, cumulative sum of proven, probable and possible reserves is referred to in the industry as "3P" (proven plus probable plus possible) where there is a 10% chance of delivering or exceeding the P10 volume.(ibid)

Resource estimates

Resource estimates are undiscovered volumes, or volumes that have not yet been drilled and flowed to surface. A non-reserve resource, by definition, does not have to be technically or commercially recoverable and can be represented by a single, or an aggregate of multiple potential accumulations, e.g. an estimated geological basin resource.

Schematic graph illustrating petroleum volumes and probabilities. Curves represent categories of oil in assessment. There is a 95% chance i.e., probability, (P95 and often referred to in the industry as F95) of at least volume V1 of economically recoverable oil, and there is a 5% chance (P05 or F05) of at least volume V2 of economically recoverable oil.

There are two non-reserve resource categories:

Contingent resources

Once a discovery has been made, prospective resources can be reclassified as contingent resources. Contingent resources are those accumulations or fields that are not yet considered mature enough for commercial development, where development is contingent on one or more conditions changing. The uncertainty in the estimates for recoverable oil & gas volumes is expressed in a probability distribution and is sub-classified based on project maturity and/or economic status (1C, 2C, 3C, ibid) and in addition are assigned a risk, or chance, to exist in reality (POS or COS).

Prospective resources

Prospective resources, being undiscovered, have the widest range in volume uncertainties and carry the highest risk or chance to be present in reality (POS or COS). At the exploration stage (before discovery) they are categorized by the wide range of volume uncertainties (typically P90-P50-P10). In the PRMS the range of volumes is classified by the abbreviations 1U, 2U and 3U again reflecting the degrees of uncertainty. Companies are commonly not required to report publicly their views of prospective resources but may choose to do so voluntarily.

Estimation techniques

The total estimated quantity (volumes) of oil and/or gas contained in a subsurface reservoir, is called oil or gas initially in place (STOIIP or GIIP respectively). However, only a fraction of in place oil & gas can be brought to the surface (recoverable), and it is only this producible fraction that is considered to be either reserves or a resource of any kind. The ratio between in place and recoverable volumes is known as the recovery factor (RF), which is determined by a combination of subsurface geology and the technology applied to extraction. When reporting oil & gas volumes, in order to avoid confusion, it should be clarified whether they are in place or recoverable volumes.

The appropriate technique for resource estimations is determined by resource maturity. There are three main categories of technique, which are used through resource maturation to differing degrees: analog (substitution), volumetric (static) and performance-based (dynamic), which are combined to help fill gaps in knowledge or data. Both probabilistic and deterministic calculation methods are commonly used to calculate resource volumes, with deterministic methods predominantly applied to reserves estimation (low uncertainty) and probabilistic methods applied to general resource estimation (high uncertainty).

TABLE II:Estimation techniques applied with decreasing resource maturity to the right

Method	Technique	1P	2P	3P	1C	2C	3C	1U	2U	3U
Analog	YTF (No segment production)							☉	☉	☉
	YTF (With segment production)							☉	☉	☉
Volumetric	Deterministic	☉	☉	☉	☉	☉	☉	☉	☉	☉
	Probabilistic models	☉	☉	☉	☉	☉	☉	☉	☉	☉
	Static reservoir models	☉	☉	☉	☉	☉	☉
Performance-based	Dynamic reservoir simulation	☉	☉	☉	☉
	Material balance	☉	☉
	Decline curve analysis	☉	☉
Unconventional reservoir	Pilot (rate transient)	☉	☉	☉	☉	☉	☉	☉	☉	☉

The combination of geological, geophysical and technical engineering constraints means that the quantification of volumes is usually undertaken by integrated technical, and commercial teams composed primarily of geoscientists and subsurface engineers, surface engineers and economists. Because the geology of the subsurface cannot be examined directly, indirect techniques must be used to estimate the size and recoverability of the resource. While new technologies have increased the accuracy of these estimation techniques, significant uncertainties still remain, which are expressed as a range of potential recoverable oil & gas quantities using probabilistic methods. In general, most early estimates of the reserves of an oil or gas field (rather than resource estimates) are conservative and tend to grow with time. This may be due to the availability of more data and/or the improved matching between predicted and actual production performance.

Appropriate external reporting of resources and reserves is required from publicly traded companies, and is an accounting process governed by strict definitions and categorisation administered by authorities regulating the stock market and complying with governmental legal requirements. Other national or industry bodies may voluntarily report resources and reserves but are not required to follow the same strict definitions and controls.

Analog (YTF) method

Analogs are applied to prospective resources in areas where there are little, or sometimes no, existing data available to inform analysts about the likely potential of an opportunity or play segment. Analog-only techniques are called yet-to-find (YTF), and involve identifying areas containing producing assets that are geologically similar to those being estimated and substituting data to match what is known about a segment. The opportunity segment can be scaled to any level depending on the specific interest of the analyst, whether at a global, country, basin, structural domain, play, license or reservoir level. YTF is conceptual and is commonly used as a method for scoping potential in frontier areas where there is no oil or gas production or where new play concepts are being introduced with perceived potential. However, analog content can also be substituted for any subsurface parameters where there are gaps in data in more mature reserves or resource settings (below).

Volumetric method

Oil & gas volumes in a conventional reservoir can be calculated using a volume equation:

Recoverable volume = Gross Rock Volume * Net/Gross * Porosity * Oil or Gas Saturation * Recovery Factor / Formation Volume Factor

Deterministic volumes are calculated when single values are used as input parameters to this equation, which could include analog content. Probabilistic volumes are calculations when uncertainty distributions are applied as input to all or some of the terms of the equation (see also Copula (probability theory)), which preserve dependencies between parameters. These geostatistical methods are most commonly applied to prospective resources that still need to be tested by the drill bit. Contingent resources are also characterized by volumetric methods with analog content and uncertainty distributions before significant production has occurred, where spatial distribution information may be preserved in a static reservoir model. Static models and dynamic flow models can be populated with analog reservoir performance data to increase the confidence in forecasting as the amount and quality of static geoscientific and dynamic reservoir performance data increase.

Performance-based methods

Once production has commenced, production rates and pressure data allow a degree of prediction on reservoir performance, which was previously characterized by substituting analog data. Analog data can still be substituted for expected reservoir performance where specific dynamic data may be missing, representing a "best technical" outcome.

Reservoir simulation

Main article: Reservoir simulation

Reservoir simulation is an area of reservoir engineering in which computer models are used to predict the flow of fluids (typically, oil, water, and gas) through porous media. The amount of oil & gas recoverable from a conventional reservoir is assessed by accurately characterising the static recoverable volumes and history matching that to dynamic flow. Reservoir performance is important because the recovery changes as the physical environment of the reservoir adjusts with every molecule extracted; the longer a reservoir has been flowing, the more accurate the prediction of remaining reserves. Dynamic simulations are commonly used by analysts to update reserves volumes, particularly in large complex reservoirs. Daily production can be matched against production forecasts to establish the accuracy of simulation models based on actual volumes of recovered oil or gas. Unlike analogs or volumetric methods above, the degree of confidence in the estimates (or the range of outcomes) increases as the amount and quality of geological, engineering and production performance data increase. These must then be compared with previous estimates, whether derived from analog, volumetric or static reservoir modelling before reserves can be adjusted and booked.

Materials balance method

The materials balance method for an oil or gas field uses an equation that relates the volume of oil, water and gas that has been produced from a reservoir and the change in reservoir pressure to calculate the remaining oil & gas. It assumes that, as fluids from the reservoir are produced, there will be a change in the reservoir pressure that depends on the remaining volume of oil & gas. The method requires extensive pressure-volume-temperature analysis and an accurate pressure history of the field. It requires some production to occur (typically 5% to 10% of ultimate recovery), unless reliable pressure history can be used from a field with similar rock and fluid characteristics.

Production decline curve method

Example of a production decline curve for an individual well

The decline curve method is an extrapolation of known production data to fit a decline curve and estimate future oil & gas production. The three most common forms of decline curves are exponential, hyperbolic, and harmonic. It is assumed that the production will decline on a reasonably smooth curve, and so allowances must be made for wells shut in and production restrictions. The curve can be expressed mathematically or plotted on a graph to estimate future production. It has the advantage of (implicitly) conflating all reservoir characteristics. It requires a sufficient production history to establish a statistically significant trend, ideally when production is not curtailed by regulatory or other artificial conditions.

Reserves growth

Experience shows that initial estimates of the size of newly discovered oil & gas fields are usually too low. As years pass, successive estimates of the ultimate recovery of fields tend to increase. The term reserve growth refers to the typical increases (but narrowing range) of estimated ultimate recovery that occur as oil & gas fields are developed and produced. Many oil-producing nations do not reveal their reservoir engineering field data and instead provide unaudited claims for their oil reserves. The numbers disclosed by some national governments are suspected of being manipulated for political reasons. In order to achieve international goals for decarbonisation, the International Energy Agency said in 2021 that countries should no longer expand exploration or invest in projects to expand reserves to meet climate goals set by the Paris Agreement.

Unconventional reservoirs

Main article: Unconventional (oil & gas) reservoir

The categories and estimation techniques framed by the PRMS above apply to conventional reservoirs, where oil & gas accumulations are controlled by hydrodynamic interactions between the buoyancy of oil & gas in water versus capillary forces. Oil or gas in unconventional reservoirs are much more tightly bound to rock matrices in excess of capillary forces and therefore require different approaches to both extraction and resource estimation. Unconventional reservoirs or accumulations also require different means of identification and include coalbed methane (CBM), basin-centered gas (low permeability), low permeability tight gas (including shale gas) and tight oil (including shale oil), gas hydrates, natural bitumen (very high viscosity oil), and oil shale (kerogen) deposits. Ultra low permeability reservoirs exhibit a half slope on a log-plot of flow-rates against time believed to be caused by drainage from matrix surfaces into adjoining fractures. Such reservoirs are commonly believed to be regionally pervasive that may be interrupted by regulatory or ownership boundaries with the potential for large oil & gas volumes, which are very hard to verify. Non-unique flow characteristics in unconventional accumulations means that commercial viability depends on the technology applied to extraction. Extrapolations from a single control point, and thereby resource estimation, are dependent on nearby producing analogs with evidence of economic viability. Under these circumstances, pilot projects may be needed to define reserves. Any other resource estimates are likely to be analog-only derived YTF volumes, which are speculative.

Cardinal virtues

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Cardinal_virtues

An image personifying the four virtues (Ballet Comique de la Reine, 1582)

The cardinal virtues are four virtues of mind and character in classical philosophy. They are prudence, justice, fortitude, and temperance. They form a virtue theory of ethics. The term cardinal comes from the Latin cardo (hinge); these four virtues are called "cardinal" because all other virtues fall under them and hinge upon them.

These virtues derive initially from Plato in Republic Book IV, 426-435. Aristotle expounded them systematically in the Nicomachean Ethics. They were also recognized by the Stoics and Cicero expanded on them. In the Christian tradition, they are also listed in the Deuterocanonical books in Wisdom of Solomon 8:7 and 4 Maccabees 1:18–19, and the Doctors Ambrose, Augustine, and Aquinas expounded their supernatural counterparts, the three theological virtues of faith, hope, and charity.

Four cardinal virtues

• Prudence (φρόνησις, phrónēsis; Latin: prudentia; also wisdom, sophia, sapientia), the ability to discern the appropriate course of action to be taken in a given situation at the appropriate time, with consideration of potential consequences; cautiousness.
• Justice (δικαιοσύνη, dikaiosýnē; Latin: iustitia): also considered as fairness; the Greek word also having the meaning righteousness.
• Courage (ἀνδρεία, andreía; Latin: fortitudo): forbearance, strength, endurance, fortitude (patience and perseverance), dedication and the ability to confront fear, uncertainty, and intimidation (bravery, boldness, valor, daring). Notably, ἀνδρεία, being closely related to ἀνήρ ("adult male"), could also be translated "manliness". Some other definitions of courage are "Andrea, virtus, spirit, heart, mettle, thumos, tenacity, gameness, resolution, bravery, boldness, valor, daring, hardihood, assertiveness, frame, gravitas, determination".
• Temperance (σωφροσύνη, sōphrosýnē; Latin: temperantia): also known as restraint, the practice of self-control, abstention, discretion, and moderation tempering the appetition. Plato considered sōphrosynē, which may also be translated as sound-mindedness, to be the most important virtue. σωφροσύνη was often used in reference to drinking and "knowing the right amount" to avoid belligerence.

Gallery, depiction of the cardinal virtues in 9th-century Europe

An early European representation of the cardinal virtues from 845 AD is found in the Vivian Bible, Paris.

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  The four virtues (in the corners) face a scene with King David (center), along with men who served David and who wrote psalms.
  
  
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  Fortitudo or Courage, from the Vivian Bible, Bibliothèque nationale, Latin 1, folio 215v.
   
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  Prydentia or Prudentia (Prudence), from the Vivian Bible.
   
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  Iustitia or Justice, from the Vivian Bible.
   
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  Temperantia or Temperance, from the Vivian Bible.

Antiquity

The four cardinal virtues appeared as a group (sometimes included in larger lists) long before they were given this title.

Hellenistic philosophy

Plato associated the four cardinal virtues with the social classes of the ideal city described in The Republic, and with the faculties of humanity. Plato narrates a discussion of the character of a good city where the following is agreed upon:

Clearly, then, it will be wise, brave, temperate [literally: healthy-minded], and just.

Temperance was most closely associated with the producing classes, the farmers and craftsmen, to moderate their animal appetites. Fortitude was assigned to the warrior class, to strengthen their fighting spirit. Prudence was assigned to the rulers, to guide their reason. Justice stood above these three to properly regulate the relations among them.

Plato sometimes lists holiness (hosiotes, eusebeia, aidos) amongst the cardinal virtues. He especially associates holiness with justice, but leaves their precise relationship unexplained.

In Aristotle's Rhetoric, we read:

The forms of Virtue are justice, courage, temperance, magnificence, magnanimity, liberality, gentleness, prudence, wisdom.

— Rhetoric 1366b1

These are expounded fully in the Nicomachean Ethics III.6-V.2.

Philo of Alexandria, a Hellenistic Jewish philosopher, also recognized the four cardinal virtues as prudence, temperance, courage, and justice. In his writings, he states:

In these words Moses intends to sketch out the particular virtues. And they also are four in number, prudence, temperance, courage, and justice.

— Philo, Philo's Works, Allegorical Interpretation 1.XIX

These virtues, according to Philo, serve as guiding principles for a virtuous and fulfilling life.

Roman philosophy

The Roman philosopher and statesman Cicero (106-43 BC), like Plato, limits the list to four virtues:

Virtue may be defined as a habit of mind (animi) in harmony with reason and the order of nature. It has four parts: wisdom (prudentiam), justice, courage, temperance.

— De Inventione, II, LIII

Cicero discusses these further in De Officiis (I, V, and following).

Seneca writes in Consolatio ad Helviam Matrem about justice (iustitia from Ancient Greek δικαιοσύνη), self-control (continentia from Ancient Greek σωφροσύνη), practical wisdom (prudentia from Ancient Greek φρόνησις) and devotion (pietas) instead of courage (fortitudo from Ancient Greek ἀνδρεία).

The Roman Emperor Marcus Aurelius discusses these in Book V:12 of Meditations and views them as the "goods" that a person should identify in one's own mind, as opposed to "wealth or things which conduce to luxury or prestige".

Suggestions of the Stoic virtues can be found in fragments in the Diogenes Laertius and Stobaeus.

The Platonist view of the four cardinal virtues is described in Definitions.

Practical wisdom or prudence (phrónēsis) is the perspicacity necessary to conduct personal business and affairs of state. It encompasses the skill to distinguish the beneficial from the detrimental, to understand the attainment of happiness, and to discern the right course of action in every situation. Its antithesis or opposite is the vice of folly.

Justice (dikaiosunê) is the harmonious alignment of one's inner self and the comprehensive integrity of the soul. It involves fostering sound discipline within each facet of our being, enabling us to live with others and extend the same regard to every individual. Additionally, justice pertains to a state's aptitude to equitably allocate resources based on individuals' deservingness, as determined by their merits. It entails refraining from undue harshness, fostering a universal perception of fairness. Furthermore, it entails embodying the qualities of a law-abiding citizen or member of society, upholding principles of social equality. Justice encompasses the formulation of laws that can be substantiated by valid justifications, leading to a society where actions align with these laws.

Moderation or temperance (sôphrosunê) is the capacity to temper the indulgence of desires and sensory pleasures within the bounds of what is customary for the individual, aligning only with experiences already familiar to the soul. It encompasses achieving a harmonious equilibrium and exercising disciplined control when it comes to overall pleasure and pain, ensuring that they remain within normal ranges. Moreover, moderation involves cultivating a harmonious relationship and a balanced rule between the soul's governing and being governed aspects. It signifies maintaining a state of natural self-reliance and exercising proper discipline as and when required by the soul. Rational consensus within the soul is essential concerning what merits admiration and what warrants disdain. This approach entails deliberate caution in one's choices, as one's selection navigates between the extremes.

Courage (andreia) can be defined as the ability to conquer fear within oneself when action is necessary. It encompasses military confidence, a deep understanding of warfare, and maintaining unwavering beliefs in the face of challenges. It involves self-discipline to overcome fear, obeying wisdom, and facing death boldly. Courage also entails maintaining sound judgment in tough situations, countering hostility, upholding virtues, remaining composed when faced with frightening (or encouraging) discussions and events, and not becoming discouraged. It reflects valuing the rule of law in our daily lives rather than diminishing its importance.

In the Bible

In the Old Testament

The cardinal virtues are listed in the deuterocanonical book Wisdom of Solomon 8:7, which reads:

She [Wisdom] teaches temperance, and prudence, and justice, and fortitude, which are such things as men can have nothing more profitable in life.

They are also found in other non-canonical scriptures like 4 Maccabees 1:18–19, which relates:

Now the kinds of wisdom are right judgment, justice, courage, and self-control. Right judgment is supreme over all of these since by means of it reason rules over the emotions.

In the New Testament

Wisdom, usually sophia, rather than Prudence (phrónēsis), is discussed extensively in all parts of the New Testament. It is a major topic of 1 Corinthians 2, where the author discusses how divine teaching and power are greater than worldly wisdom.

Justice (δικαιοσύνη, dikaiosýnē) is taught in the gospels, where most translators give it as "righteousness".

Plato's word for Fortitude (ἀνδρεία) is not present in the New Testament, but the virtues of steadfastness (ὑπομονή, hypomonē) and patient endurance (μακροθυμία, makrothymia) are praised. Paul exhorts believers to "act like men" (ἀνδρίζομαι, andrizomai, 1 Corinthians 16:13).

Temperance (σωφροσύνη, sōphrosýnē), usually translated "sobriety," is present in the New Testament, along with self-control (ἐγκράτεια, egkrateia).

In Christian tradition

Catholic moral theology drew from both the Wisdom of Solomon and the Fourth Book of Maccabees in developing its thought on the virtues. Ambrose (c. 330s – c. 397) used the expression "cardinal virtues":

And we know that there are four cardinal virtues - temperance, justice, prudence, and fortitude.

— Commentary on Luke, V, 62

Augustine of Hippo, discussing the morals of the church, described them:

For these four virtues (would that all felt their influence in their minds as they have their names in their mouths!), I should have no hesitation in defining them: that temperance is love giving itself entirely to that which is loved; fortitude is love readily bearing all things for the sake of the loved object; justice is love serving only the loved object, and therefore ruling rightly; prudence is love distinguishing with sagacity between what hinders it and what helps it.

— De moribus eccl., Chap. xv

In relation to the theological virtues

The "cardinal" virtues are not the same as the three theological virtues: Faith, Hope, and Charity (Love), named in 1 Corinthians 13.

And now these three remain: faith, hope, and love. But the greatest of these is love.

Because of this reference, a group of seven virtues is sometimes listed by adding the four cardinal virtues (prudence, temperance, fortitude, justice) and three theological virtues (faith, hope, charity). While the first four date back to Greek philosophers and were applicable to all people seeking to live moral lives, the theological virtues appear to be specific to Christians as written by Paul in the New Testament.

Efforts to relate the cardinal and theological virtues differ. Augustine sees faith as coming under justice. Beginning with a wry comment about the moral mischief of pagan deities, he writes:

They [the pagans] have made Virtue also a goddess, which, indeed, if it could be a goddess, had been preferable to many. And now, because it is not a goddess, but a gift of God, let it be obtained by prayer from Him, by whom alone it can be given, and the whole crowd of false gods vanishes. For as much as they have thought proper to distribute virtue into four divisions - prudence, justice, fortitude, and temperance - and as each of these divisions has its own virtues, faith is among the parts of justice, and has the chief place with as many of us as know what that saying means, ‘The just shall live by faith.’

— City of God, IV, 20

Dante Alighieri also attempts to relate the cardinal and theological virtues in his Divine Comedy, most notably in the complex allegorical scheme drawn in Purgatorio XXIX to XXXI. Depicting a procession in the Garden of Eden (which the author situates at the top of the mountain of purgatory), Dante describes a chariot drawn by a gryphon and accompanied by a vast number of figures, among which stand three women on the right side dressed in red, green, and white, and four women on the left, all dressed in purple. The chariot is generally understood to represent the holy church, with the women on right and left representing the theological and cardinal virtues respectively. The exact meaning of the allegorical women's role, behaviour, interrelation, and color-coding remains a matter of literary interpretation.

In relation to the seven deadly sins

In the High Middle Ages, some authors opposed the seven virtues (cardinal plus theological) to the seven deadly sins. However, “treatises exclusively concentrating on both septenaries are actually quite rare.” and “examples of late medieval catalogues of virtues and vices which extend or upset the double heptad can be easily multiplied.” And there are problems with this parallelism:

The opposition between the virtues and the vices to which these works allude despite the frequent inclusion of other schemes may seem unproblematic at first sight. The virtues and the vices seem to mirror each other as positive and negative moral attitudes, so that medieval authors, with their keen predilection for parallels and oppositions, could conveniently set them against each other. … Yet artistic representations such as Conrad’s trees are misleading in that they establish oppositions between the principal virtues and the capital vices which are based on mere juxtaposition. As to content, the two schemes do not match each other. The capital vices of lust and avarice, for instance, contrast with the remedial virtues of chastity and generosity, respectively, rather than with any theological or cardinal virtue; conversely, the virtues of hope and prudence are opposed to despair and foolishness rather than to any deadly sin. Medieval moral authors were well aware of the fact. Actually, the capital vices are more often contrasted with the remedial or contrary virtues in medieval moral literature than with the principal virtues, while the principal virtues are frequently accompanied by a set of mirroring vices rather than by the seven deadly sins.

Contemporary thought

Jesuit scholars Daniel J. Harrington and James F. Keenan, in their Paul and Virtue Ethics (2010), argue for seven "new virtues" to replace the classical cardinal virtues in complementing the three theological virtues, mirroring the seven earlier proposed in Bernard Lonergan's Method in Theology (1972): "be humble, be hospitable, be merciful, be faithful, reconcile, be vigilant, and be reliable".

Allegory

Fresco with allegories of the four cardinal virtues in the ‘’Assunta’’ church in Manerba del Garda.

The Tomb of Sir John Hotham, supported by figures of the cardinal virtues.

The Cardinal Virtues are often depicted as female allegorical figures. These were a popular subject for funerary sculpture. The attributes and names of these figures may vary according to local tradition.

Yves Decadt, a Flemish artist, has created a series of artworks titled “Falling Angels: Allegories about the 7 Sins and 7 Virtues for Falling Angels and other Curious Minds”. The series explores the topic of morality, sins, and virtues, which have dominated Western cultures for more than 2000 years. In this work, Decadt follows in the footsteps of Pieter Breughel, who made a series of sketches on the 7 sins and 7 virtues about 500 years ago.   The work takes the viewer on an adventurous trip through time and across the barriers and edges of reality, mythology, religion, and culture.

The virtues in art

Four cardinal virtues; Louvre, Paris. Brooklyn Museum Archives, Goodyear Archival Collection.

In many churches and artwork the Cardinal Virtues are depicted with symbolic items:

Justice

sword, balance and scales, a crown

Temperance

wheel, bridle and reins, vegetables and fish, cup, water and wine in two jugs

Fortitude

armor, club, with a lion, palm, tower, a yoke, a broken column

Prudence

book, scroll, mirror, an attacking serpent

The cardinal virtues as depicted on the tomb of Pope Clement II in Bamberg Cathedral

• 
  Iustitia (Justice), with balance and scales
   
• 
  Temperantia (Temperance), with water and wine in two jugs
   
• 
  Fortitudo (Fortitude), with a lion
   
• 
  Prudentia (Prudence), with a serpent

Notable depictions include sculptures on the tomb of Francis II, Duke of Brittany and the tomb of John Hotham. They were also depicted in the garden at Edzell Castle.

Tree of the knowledge of good and evil

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Tree_of_the_knowledge_of_good_and_evil

Adam and Eve - Paradise, the fall of man as depicted by Lucas Cranach the Elder, the Tree of knowledge of good and evil is on the right

In Christianity and Judaism, the tree of the knowledge of good and evil (Tiberian Hebrew: עֵץ הַדַּעַת טוֹב וָרָע, romanized: ʿêṣ had-daʿaṯ ṭōḇ wā-rāʿ, [ʕesˤ hadaʕaθ tˤov wɔrɔʕ]; Latin: Lignum scientiae boni et mali) is one of two specific trees in the story of the Garden of Eden in Genesis 2–3, along with the tree of life. Alternatively, some scholars have argued that the tree of the knowledge of good and evil is just another name for the tree of life.

In Genesis

Narrative

Genesis 2 narrates that God places the man, Adam, in a garden with trees whose fruits he may eat, but forbids him to eat from "the tree of the knowledge of good and evil". God forms a woman, Eve, after this command is given. In Genesis 3, a serpent persuades Eve to eat from its forbidden fruit and she also lets Adam taste it. Consequently, God expels them from the garden.

Meaning of good and evil

The phrase in Hebrew, טוֹב וָרָע (tov wa-raʿ) literally translates as "good and evil". This may be an example of the type of figure of speech known as merism, a literary device that pairs opposite terms together in order to create a general meaning, so that the phrase "good and evil" would simply imply "everything". This is seen in the Egyptian expression "evil-good", which is normally employed to mean "everything". However, if "tree of the knowledge of good and evil" is to be understood to mean a tree whose fruit imparts knowledge of everything, this phrase does not necessarily denote a moral concept. This view is held by several scholars.

Given the context of disobedience to God, other interpretations of the implications of this phrase also demand consideration. Robert Alter emphasizes the point that when God forbids the man to eat from that particular tree, he says that if he does so, he is "doomed to die." The Hebrew behind this is in a form regularly used in the Hebrew Bible for issuing death sentences.

However, there are myriad modern scholarly interpretations regarding the term הדעת טוב ורע (Hada'at tov wa-ra "the knowledge of good and evil") in Genesis 2–3, such as wisdom, omniscience, sexual knowledge, moral discrimination, maturity, and other qualities. According to scholar Nathan French, the term likely means "the knowledge for administering reward and punishment," suggesting that the knowledge forbidden by Yahweh and yet acquired by the humans in Genesis 2–3 is the wisdom for wielding ultimate power.

Religious views

Judaism

Jewish sources suggest different possible identities for the tree: a fig tree (as fig leaves were used to clothe Adam and Eve after the sin), a grape vine (as "nothing brings wailing to the world like wine"), a stalk of wheat (as "a child does not know how to say Father and Mother until he tastes grain"), an etrog (as the description in Genesis 3:6 matches the etrog fruit's beautiful appearance, or else the etrog tree's allegedly tasty bark), or a nut tree.

In Jewish tradition, the Tree of Knowledge and the eating of its fruit represents the beginning of the mixture of good and evil together. Before that time, the two were separate, and evil had only a nebulous existence in potential. While free choice did exist before eating the fruit, evil existed as an entity separate from the human psyche, and it was not in human nature to desire it. Eating and internalizing the forbidden fruit changed this, and thus was born the yetzer hara, the evil inclination.

According to Rashi, the sin came about because Eve added an additional clause to the divine command: "Neither shall you touch it." By saying this, Eve added to YHWH's command, and thereby came to detract from it, as it is written: "Do not add to His Words" (Proverbs 30:6). However, In Legends of the Jews, it was Adam who had devoutly forbidden Eve to touch the tree even though God had only mentioned the eating of the fruit.

According to one source, Eve also fed the fruit to the animals, leading to their mortality as well.

In the Kabbalah, the sin of the Tree of Knowledge (called Cheit Eitz HaDa'at) brought about the great task of beirurim, sifting through the mixture of good and evil in the world to extract and liberate the sparks of holiness trapped therein. Since evil no longer had independent existence, it henceforth depended on holiness to draw down the Divine life-force, on whose "leftovers" it then feeds and derives existence. Once evil is separated from holiness through beirurim, its source of life is cut off, causing the evil to disappear. This is accomplished through observance of the 613 commandments in the Torah, which deal primarily with physical objects wherein good and evil are mixed together. The sin of the Tree caused God's presence (Shechinah) to depart from earth; in kabbalah, the task of beirurim rectifies the sin of the Tree and causes the Shechinah to return.

Christianity

A marble bas relief by Lorenzo Maitani on the Orvieto Cathedral, Italy, depicts Eve and the tree.

In Christian tradition, consuming the fruit of the tree of knowledge of good and evil was the original sin committed by Adam and Eve that led to the fall of man in Genesis 3.

Augustine of Hippo taught that the "tree" should be understood both symbolically and as a real tree – similarly to Jerusalem being both a real city and a figure of Heavenly Jerusalem. Augustine underlined that the fruits of that tree were not evil by themselves, because everything that God created "was good" (Genesis 1:12). It was disobedience of Adam and Eve, who had been told by God not to eat off the tree (Genesis 2:17), that caused disorder in the creation, thus humanity inherited sin and guilt from Adam and Eve's sin.

In Western Christian art, the fruit of the tree is commonly depicted as the apple, which originated in central Asia. This depiction may have originated as a Latin pun: by eating the mālum (apple), Eve contracted malum (evil). According to the Bible, there is nothing to show the forbidden fruit of the tree of the knowledge of good and evil was necessarily an apple.

Gnosticism

Uniquely, the Gnostic religion held that the tree was entirely positive or even sacred. Per this saga, it was the archons who told Adam and Eve not to eat from its fruit, before lying to them by claiming they would die after tasting it. Later in the story, an instructor is sent from the Pleroma by the aeons to save humanity and reveal gnosis. This savior does so by telling Adam and Eve that eating the fruit is the way into salvation. Examples of the narrative can be found within the Gnostic manuscripts On the Origin of the World and the Secret Book of John.

Manichaeism, which has been considered a Gnostic sect, echoes these notions as well, presenting the primordial aspect of Jesus as the instructor.

Islam

See also: Tree of life (Quran)

The Quran never refers to the tree as the "tree of the knowledge of good and evil" but rather typically refers to it as "the tree" or (in the words of Iblis) as the "tree of immortality." Muslims believe that when God created Adam and Eve, he told them that they could enjoy everything in the Garden except this tree and so Satan appeared to them, telling them the only reason God forbade them to eat from the tree was that they would become angels or immortal.

When they ate from this tree, their nakedness appeared to them, and they began to sew together leaves from the Garden for their covering. The Quran mentions the sin as being a 'slip'. Consequently, they repented to God and asked for his forgiveness, and were forgiven. In Islamic tradition, the forbidden fruit is considered wheat or barley, not an apple as within Western Christian tradition.

In Quran Al-A'raf 27, God states:

[O] Children of Adam! Let not Satan tempt you as he brought your parents out of the Garden, stripping them of their garments to show them their shameful parts. Surely he [Satan] sees you, he and his tribe, from where you see them not. We have made the Satans the friends of those who do not believe.

Similar depictions in Akkadian seal

A cylinder seal, known as the Adam and Eve cylinder seal, from post-Akkadian periods in Mesopotamia (c. 23rd – 22nd century BCE) has been linked to the Adam and Eve story. Assyriologist George Smith (1840–1876) described the seal as having two facing figures (male and female) seated on each side of a tree, holding out their hands to the fruit, while between their backs is a serpent, giving evidence that the fall of man account was known in early times of Babylonia.

The British Museum disputes this interpretation, and holds that it is a common image from the period depicting a male deity being worshipped by a woman, with no reason to connect the scene with the Book of Genesis.