Glauber

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Glauber is a scientific discovery method written in the context of computational philosophy of science. It is related to machine learning in artificial intelligence.

Contents

Glauber was written, among other programs, by Pat Langley, Herbert A. Simon, G. Bradshaw and J. Zytkow to demonstrate how scientific discovery may be obtained by problem solving methods, in their book Scientific Discovery, Computational Explorations on the Creative Mind. [1]

Their programs simulate historical scientific discoveries based on the empirical evidence known at the time of discovery.

Glauber was named after Johann Rudolph Glauber, a 17th-century alchemist whose work helped to develop acid-base theory. Glauber (the method) rediscovers the law of acid-alkali reactions producing salts, given the qualities of substances and observed facts, the result of mixing substances. From that knowledge Glauber discovers that substances that taste bitter react with substances tasting sour, producing substances tasting salty.

In few words, the law:

Acid + Alkali --> Salt

Glauber was designed by Pat Langley as part of his work on discovery heuristics in an attempt to have a computer automatically review a host of values and characteristics and make independent analyses from them. In the case of Glauber, the goal was to have an autonomous application that could estimate, even perfectly describe, the nature of a given chemical compound by comparing it to related substances. Langley formalized and compiled Glauber in 1983.

The software were supplied with information about a variety of materials as they had been described by 17-18th century chemists, before most of modern chemical knowledge had been uncovered or invented. Qualitative descriptions like taste, rather than numerical data such as molecular weight, were programmed into the application. Chemical reactions that were known in that era and the distinction between reactants and products were also provided. From this knowledge, Glauber was to figure out which substances were acids, bases, and salts without any quantitative information. The system examined chemical substances and all of their most likely reactions and correlates the expected taste and related acidity or saltiness according to the rule that acids and bases produce salts.

Glauber was a very successful advance in theoretical chemistry as performed by computer and it, along with similar systems developed by Herbert A. Simon including Stahl (which examines oxidation) and DALTON (which calculates atomic weight), helped form the groundwork of all current automated chemical analysis.

The Glauber method

Information representation (data structures)

Glauber uses two predicates: Reacts and Has-Quality, represented in Lisp lists as follows:

(Reacts Inputs {reactant1 reactant2 ...} Outputs {product1 product2 ...})
(Has-Quality Object {substance} quality {value})

For their experiment the authors used the following facts:

(Reacts Inputs {HCl NaOH} Outputs {NaCl})
(Reacts Inputs {HCl KOH} Outputs {KCl})
(Reacts Inputs {HNO3 NaOH} Outputs {NaNO3})
(Reacts Inputs {HNO3 KOH} Outputs {KNO3 })
(Has-Quality Object {HCl} Tastes {Sour})
(Has-Quality Object {HNO3} Tastes {Sour })
(Has-Quality Object {NaOH} Tastes {Bitter})
(Has-Quality Object {KOH} Tastes {Bitter})
(Has-Quality Object {NaCl} Tastes {Salty})
(Has-Quality Object {NaNO3} Tastes {Salty})
(Has-Quality Object {KCl} Tastes {Salty})
(Has-Quality Object {KNO3} Tastes {Salty})

Discovering the following law and equivalence classes:

Salts: {KNO3, KCl, NaNO3, NaCl}
Acids: {HCl, HNO3}
Alkalis: {NaOH, KOH}
∀ alkali ∀ acid ∃ salt (Reacts Inputs {acid, alkali} Outputs {salt})
∀ salt (Has-Quality Object {salt} Tastes {Salty})
∀ acid (Has-Quality Object {acid} Tastes {Sour})
∀ alkali (Has-Quality Object {alkali} Tastes {Bitter})

The modern notation with strings like: NaOH, HCl, etc., is used just as short substance names. Here they do not mean the chemical structure of the substances, which was not known at the time of the discovery; the program works with any name used in the 17th century like aqua regia, muriatic acid, etc.

Procedures

Glauber is based in two procedures: Form-Class and Determine-Quantifier. The procedure Form-Class generalize the Reacts predicates by replacing the substance names by variables ranging on equivalence classes determined by a quality whose value distinguishes the substances in each class. In the experiment designed by its authors, the substances are partitioned in three classes based in the value of the taste quality according on their value: acids (sour), alkalis (bitter) and salts (salty).

Glauber main procedure

Input: Reacts and Has-Quality predicate sets
Output: On success returns a generalized version of the Reacts predicate whose variables range over the equivalence classes and a new Class predicate which is like Has-Quality having a name-class instead of substance name: (Has-Quality {class-name} quality {value})
  1. If there are no more substance names in the Reacts predicates then finish
  2. process the Reacts predicates with the Form-Class procedure
  3. process the result of the previous step with Determine-Quantifier
  4. go to step 3

Form-Class

Input: the Reacts and Has-Quality predicate sets
Output: a new substances class, a new Has-Quality and a new Reacts predicate set
  1. Count the number of occurrences of each quality {value} in the Has-Quality predicates
  2. Select the quality value with the largest number of occurrences, which substances are in the Reacts predicates
  3. Create a name for the class
  4. Generate a new Has-Quality predicate set removing all the predicates in Has-Quality with the selected quality {value} and adding the predicate (Has-Quality {class-name} quality {value}) to the Class predicates where class-name is the name obtained in step 3
  5. Generate a new Reacts predicate set by replacing the name of the substance in the class formed in the step 2 by the name created in step 3
  6. Create a new class extension by associating the name generated on step 3 with the set of all substances on the class selected on step 2

Determine-Quantifier

Input: the Reacts, Has-Quality and Class (generated by Form-Class) predicate sets
Output: An intentional quantified class corresponding to the extensional class generated by Form-Class, a new Reacts predicate set extended with the appropriate quantifier of the last discovered class received from Form-Class
  1. Universally quantify the rule to determine the class
    (Has-Quality {class-name} quality {value}) => (∀ class-name (Has-Quality {class-name} quality {value}))
  2. Generate Reacts predicates replacing each substance in the new class for its class-name in the Reacts predicates
  3. if all the predicates generated in the previous step are contained in the original set
    then quantify universally
    else quantify existentially


Related Research Articles

Acid Type of chemical substance

An acid is a molecule or ion capable of donating a proton (hydrogen ion H+) (a Brønsted–Lowry acid), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid).

In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal chemical element. An alkali also can be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline is commonly, and alkalescent less often, used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases.

Acid–base reaction Chemical reaction

An acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.

In chemistry, a salt is a chemical compound consisting of an ionic assembly of cations and anions. Salts are composed of related numbers of cations and anions so that the product is electrically neutral. These component ions can be inorganic, such as chloride (Cl−), or organic, such as acetate ; and can be monatomic, such as fluoride (F−) or polyatomic, such as sulfate.

Ammonium cation, protonated ammonia

The ammonium cation is a positively charged polyatomic ion with the chemical formula NH+
4. It is formed by the protonation of ammonia (NH3). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary ammonium cations (NR+
4), where one or more hydrogen atoms are replaced by organic groups (indicated by R).

Base (chemistry) substance that can react with an acid, accepting hydrogen ions (protons) or more generally, donating a pair of valence electrons

In chemistry, there are three definitions in common use of the word base, known as Arrhenius bases, Brønsted bases and Lewis bases. All definitions agree that bases are substances which react with acids as originally proposed by G.-F. Rouelle in the mid-18th century.

The compound hydrogen chloride has the chemical formula HCl and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl.

Corrosive substance Strong alkaline chemicals that destroy soft body tissues resulting in a deep, penetrating type of burn, in contrast to corrosives, that result in a more superficial type of damage via chemical means or inflammation. Caustics are usually hydroxides.

A corrosive substance is one that will damage or destroy other substances with which it comes into contact by means of a chemical reaction.

Saponification is a process that involves conversion of fat, oil, or lipid into soap and alcohol by the action of heat in the presence of aqueous alkali. Soaps are salts of fatty acids and fatty acids are mono that have long carbon chains e.g. sodium palmitate.

Nitrous acid chemical compound

Nitrous acid is a weak and monoprotic acid known only in solution, in the gas phase and in the form of nitrite salts. Nitrous acid is used to make diazonium salts from amines. The resulting diazonium salts are reagents in azo coupling reactions to give azo dyes.

Ammonium bicarbonate chemical compound

Ammonium bicarbonate is an inorganic compound with formula (NH4)HCO3, simplified to NH5CO3. The compound has many names, reflecting its long history. Chemically speaking, it is the bicarbonate salt of the ammonium ion. It is a colourless solid that degrades readily to carbon dioxide, water and ammonia.

Neutralization (chemistry) chemical reaction

In chemistry, neutralization or neutralisation is a chemical reaction in which acid and a base react quantitatively with each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutralized solution depends on the acid strength of the reactants.

Potassium sulfate chemical compound

Potassium sulfate (US) or potassium sulphate (UK), also called sulphate of potash (SOP), arcanite, or archaically potash of sulfur, is the inorganic compound with formula K2SO4, a white water-soluble solid. It is commonly used in fertilizers, providing both potassium and sulfur.

Acid salts are a class of salts that produce an acidic solution after being dissolved in a solvent. Its formation as a substance has a greater electrical conductivity than that of the pure solvent. An acidic solution formed by acid salt is made during partial neutralization of diprotic or polyprotic acids. A half-neutralization occurs due to the remaining of replaceable hydrogen atoms from the partial dissociation of weak acids that have not been reacted with hydroxide ions (OH−) to create water molecules. Acid salt is an ionic compound consisted of an anion, contributed from a weak parent acid, and a cation, contributed from a strong parent base.

Xanthate

Xanthate usually refers to a salt with the formula ROCS−
2M+
 (R = alkyl; M+ = Na+, K+), thus O-esters of dithiocarbonate. The name xanthates is derived from Greek ξανθός xanthos, meaning “yellowish, golden”, and indeed most xanthate salts are yellow. They were discovered and named in 1823 by Danish chemist William Christopher Zeise. These organosulfur compounds are important in two areas: the production of cellophane and related polymers from cellulose and (in mining) for extraction of certain ores. They are also versatile intermediates in organic synthesis. Xanthates also refer to esters of xanthic acid. These esters have the structure ROC(=S)SR′.

An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bond to oxygen that can dissociate to produce the H+ cation and the anion of the acid.

The electronic tongue is an instrument that measures and compares tastes.

Beefy meaty peptide 8-amino acid long peptide providing a beef flavor

Beefy meaty peptide, also known as delicious peptide and abbreviated as BMP, is an 8-amino acid long peptide that has been identified as giving a beefy flavour to foods in which it is present. It was isolated from beef soup by Yamasaki and Maekawa in 1978. Ongoing research since its discovery by Yamasaki and Maekawa has provided general support for the presence of its flavor-imparting properties. However, due to its high production cost, the peptide's potential for widespread application in the food industry has yet to be realized, prompting current research efforts to focus on finding a method of mass-production for the peptide.

Hydrochloric acid strong mineral acid

Hydrochloric acid or muriatic acid is a colorless inorganic chemical system with the formula HCl. Hydrochloric acid has a distinctive pungent smell. It is classified as strongly acidic and can attack the skin over a wide composition range, since the hydrogen chloride completely dissociates in an aqueous solution.

Taste Sense of chemicals on the tongue

The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, mostly on the tongue. Taste, along with smell (olfaction) and trigeminal nerve stimulation, determines flavors of food and other substances. Humans have taste receptors on taste buds and other areas including the upper surface of the tongue and the epiglottis. The gustatory cortex is responsible for the perception of taste.

References

  1. ↑ Langley, Patrick; Simon, Herbert A.; Bradshaw, G.; Zytcow, J. (1987). Scientific Discovery, Computational Explorations on the Creative Mind . Cambridge, Massachusetts: MIT Press. ISBN   0-262-62052-9.
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