Evidence for a proposition is what supports the proposition. It is usually understood as an indication that the proposition is true . The exact definition and role of evidence vary across different fields. In epistemology , evidence is what justifies beliefs or what makes it rational to hold a certain doxastic attitude. For example, a perceptual experience of a tree may serve as evidence to justify the belief that there is a tree. In this role, evidence is usually understood as a private mental state . In phenomenology , evidence is limited to intuitive knowledge, often associated with the controversial assumption that it provides indubitable access to truth.
137-424: In science and history, consilience (also convergence of evidence or concordance of evidence ) is the principle that evidence from independent, unrelated sources can "converge" on strong conclusions. That is, when multiple sources of evidence are in agreement, the conclusion can be very strong even when none of the individual sources of evidence is significantly so on its own. Most established scientific knowledge
274-446: A 2D gel electrophoresis . The Bradford assay is a molecular biology technique which enables the fast, accurate quantitation of protein molecules utilizing the unique properties of a dye called Coomassie Brilliant Blue G-250. Coomassie Blue undergoes a visible color shift from reddish-brown to bright blue upon binding to protein. In its unstable, cationic state, Coomassie Blue has a background wavelength of 465 nm and gives off
411-415: A consensus to emerge since the different parties may be unable to agree even on what the evidence is. When understood in the widest sense, it is not controversial that some form of theory-ladenness exists. But it is questionable whether it constitutes a serious threat to scientific evidence when understood in this sense. Philosophers in the 20th century started to investigate the "evidential relation",
548-405: A criminal act. The focus of criminal evidence is to connect physical evidence and reports of witnesses to a specific person. The path that physical evidence takes from the scene of a crime or the arrest of a suspect to the courtroom is called the chain of custody . In a criminal case, this path must be clearly documented or attested to by those who handled the evidence. If the chain of evidence
685-519: A meter stick – in all three cases, the answer should be approximately the same. For the same reason, different dating methods in geochronology should concur, a result in chemistry should not contradict a result in geology, etc. The word consilience was originally coined as the phrase "consilience of inductions" by William Whewell ( consilience refers to a "jumping together" of knowledge). The word comes from Latin com- "together" and -siliens "jumping" (as in resilience). Consilience requires
822-739: A plasmid ( expression vector ). The plasmid vector usually has at least 3 distinctive features: an origin of replication, a multiple cloning site (MCS), and a selective marker (usually antibiotic resistance ). Additionally, upstream of the MCS are the promoter regions and the transcription start site, which regulate the expression of cloned gene. This plasmid can be inserted into either bacterial or animal cells. Introducing DNA into bacterial cells can be done by transformation via uptake of naked DNA, conjugation via cell-cell contact or by transduction via viral vector. Introducing DNA into eukaryotic cells, such as animal cells, by physical or chemical means
959-403: A case. The decision-maker, often a jury, but sometimes a judge decides whether the burden of proof has been fulfilled. After deciding who will carry the burden of proof, the evidence is first gathered and then presented before the court: In a criminal investigation, rather than attempting to prove an abstract or hypothetical point, the evidence gatherers attempt to determine who is responsible for
1096-451: A density gradient, which separated the DNA molecules based on their density. The results showed that after one generation of replication in the N medium, the DNA formed a band of intermediate density between that of pure N DNA and pure N DNA. This supported the semiconservative DNA replication proposed by Watson and Crick, where each strand of the parental DNA molecule serves as a template for
1233-526: A host's immune system cannot recognize the bacteria and it kills the host. The other, avirulent, rough strain lacks this polysaccharide capsule and has a dull, rough appearance. Presence or absence of capsule in the strain, is known to be genetically determined. Smooth and rough strains occur in several different type such as S-I, S-II, S-III, etc. and R-I, R-II, R-III, etc. respectively. All this subtypes of S and R bacteria differ with each other in antigen type they produce. The Avery–MacLeod–McCarty experiment
1370-456: A labeled complement of a sequence of interest. The results may be visualized through a variety of ways depending on the label used; however, most result in the revelation of bands representing the sizes of the RNA detected in sample. The intensity of these bands is related to the amount of the target RNA in the samples analyzed. The procedure is commonly used to study when and how much gene expression
1507-518: A mixture of proteins. Western blots can be used to determine the size of isolated proteins, as well as to quantify their expression. In western blotting , proteins are first separated by size, in a thin gel sandwiched between two glass plates in a technique known as SDS-PAGE . The proteins in the gel are then transferred to a polyvinylidene fluoride (PVDF), nitrocellulose, nylon, or other support membrane. This membrane can then be probed with solutions of antibodies . Antibodies that specifically bind to
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#17327910276831644-578: A more modern usage, the plural form is also used. In academic discourse, evidence plays a central role in epistemology and in the philosophy of science . Reference to evidence is made in many different fields, like in science, in the legal system, in history, in journalism and in everyday discourse. A variety of different attempts have been made to conceptualize the nature of evidence. These attempts often proceed by starting with intuitions from one field or in relation to one theoretical role played by evidence and go on to generalize these intuitions, leading to
1781-455: A neutral arbiter between competing theories. Measurements of Mercury's "anomalous" orbit , for example, are seen as evidence that confirms Einstein 's theory of general relativity . Philosophers of science tend to understand evidence not as mental states but as observable physical objects or events, secured by following the scientific method . The problems of underdetermination and theory-ladenness are two obstacles that threaten to undermine
1918-492: A perceived failure to fulfill the burden of proof. Two principal considerations are: The latter question depends on the nature of the point under contention and determines the quantity and quality of evidence required to meet the burden of proof. In a criminal trial in the United States, for example, the prosecution carries the burden of proof since the defendant is presumed innocent until proven guilty beyond
2055-453: A philosophical debate , there is an implicit burden of proof on the party asserting a claim, since the default position is generally one of neutrality or unbelief. Each party in a debate will therefore carry the burden of proof for any assertion they make in the argument, although some assertions may be granted by the other party without further evidence. If the debate is set up as a resolution to be supported by one side and refuted by another,
2192-447: A pre-existing hypothesis. Logical positivists , on the other hand, held that this priority is semantic in nature, i.e. that the meanings of the theoretical terms used in the hypothesis are determined by what would count as evidence for them. Counterexamples for this view come from the fact that our idea of what counts as evidence may change while the meanings of the corresponding theoretical terms remain constant. The most plausible view
2329-530: A proposition is evidence for a hypothesis if it entails the "development of the hypothesis". Intuitively, the development of the hypothesis is what the hypothesis states if it was restricted to only the individuals mentioned in the evidence. In the case above, we have the hypothesis " ∀ x ( s w a n ( x ) → w h i t e ( x ) ) {\displaystyle \forall x(swan(x)\rightarrow white(x))} " (all swans are white) which, when restricted to
2466-408: A reasonable doubt . Similarly, in most civil procedures , the plaintiff carries the burden of proof and must convince a judge or jury that the preponderance of the evidence is on their side. Other legal standards of proof include "reasonable suspicion", "probable cause" (as for arrest ), " prima facie evidence", "credible evidence", "substantial evidence", and "clear and convincing evidence". In
2603-436: A reddish-brown color. When Coomassie Blue binds to protein in an acidic solution, the background wavelength shifts to 595 nm and the dye gives off a bright blue color. Proteins in the assay bind Coomassie blue in about 2 minutes, and the protein-dye complex is stable for about an hour, although it is recommended that absorbance readings are taken within 5 to 20 minutes of reaction initiation. The concentration of protein in
2740-535: A serious problem to be reconciled. For example, in the 19th century, the Sun appeared to be no more than 20 million years old, but the Earth appeared to be no less than 300 million years (resolved by the discovery of nuclear fusion and radioactivity , and the theory of quantum mechanics ); or current attempts to resolve theoretical differences between quantum mechanics and general relativity . Because of consilience,
2877-408: A single slide. Each spot has a DNA fragment molecule that is complementary to a single DNA sequence . A variation of this technique allows the gene expression of an organism at a particular stage in development to be qualified ( expression profiling ). In this technique the RNA in a tissue is isolated and converted to labeled complementary DNA (cDNA). This cDNA is then hybridized to the fragments on
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#17327910276833014-460: A symptom of the truth of the hypothesis. Against this approach, it has been argued that it is too liberal because it allows accidental generalizations as evidence. Finding a nickel in one's pocket, for example, raises the probability of the hypothesis that "All the coins in my pockets are nickels". But, according to Alvin Goldman , it should not be considered evidence for this hypothesis since there
3151-436: A universal definition of evidence. One important intuition is that evidence is what justifies beliefs . This line of thought is usually followed in epistemology and tends to explain evidence in terms of private mental states, for example, as experiences, other beliefs or knowledge. This is closely related to the idea that how rational someone is, is determined by how they respond to evidence. Another intuition, which
3288-462: A viewpoint on the interdisciplinary relationships between molecular biology and other related fields. While researchers practice techniques specific to molecular biology, it is common to combine these with methods from genetics and biochemistry . Much of molecular biology is quantitative, and recently a significant amount of work has been done using computer science techniques such as bioinformatics and computational biology . Molecular genetics ,
3425-448: Is accumulated through observations of phenomena that occur in the natural world, or which are created as experiments in a laboratory or other controlled conditions. Scientists tend to focus on how the data used during statistical inference are generated. Scientific evidence usually goes towards supporting or rejecting a hypothesis . The burden of proof is on the person making a contentious claim. Within science, this translates to
3562-439: Is also a long tradition of studying biomolecules "from the ground up", or molecularly, in biophysics . Molecular cloning is used to isolate and then transfer a DNA sequence of interest into a plasmid vector. This recombinant DNA technology was first developed in the 1960s. In this technique, a DNA sequence coding for a protein of interest is cloned using polymerase chain reaction (PCR), and/or restriction enzymes , into
3699-485: Is an apparent explanation of why scientific knowledge determined in one field of inquiry has often helped in understanding other fields. Consilience does not forbid deviations: in fact, since not all experiments are perfect, some deviations from established knowledge are expected. However, when the convergence is strong enough, then new evidence inconsistent with the previous conclusion is not usually enough to outweigh that convergence. Without an equally strong convergence on
3836-439: Is becoming more affordable and used in many different scientific fields. This will drive the development of industries in developing nations and increase accessibility to individual researchers. Likewise, CRISPR-Cas9 gene editing experiments can now be conceived and implemented by individuals for under $ 10,000 in novel organisms, which will drive the development of industrial and medical applications. The following list describes
3973-620: Is broken, a defendant may be able to persuade the judge to declare the evidence inadmissible . Presenting evidence before the court differs from the gathering of evidence in important ways. Gathering evidence may take many forms; presenting evidence that tends to prove or disprove the point at issue is strictly governed by rules. Failure to follow these rules leads to any number of consequences. In law, certain policies allow (or require) evidence to be excluded from consideration based either on indicia relating to reliability, or broader social concerns. Testimony (which tells) and exhibits (which show) are
4110-436: Is built. This evidence-based method is meant to make it possible for philosophy to overcome many of the traditionally unresolved disagreements and thus become a rigorous science. This far-reaching claim of phenomenology, based on absolute certainty, is one of the focal points of criticism by its opponents. Thus, it has been argued that even knowledge based on self-evident intuition is fallible. This can be seen, for example, in
4247-413: Is called transfection . Several different transfection techniques are available, such as calcium phosphate transfection, electroporation , microinjection and liposome transfection . The plasmid may be integrated into the genome , resulting in a stable transfection, or may remain independent of the genome and expressed temporarily, called a transient transfection. DNA coding for a protein of interest
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4384-410: Is centrifuged and the pellet which contains E.coli cells was checked and the supernatant was discarded. The E.coli cells showed radioactive phosphorus, which indicated that the transformed material was DNA not the protein coat. The transformed DNA gets attached to the DNA of E.coli and radioactivity is only seen onto the bacteriophage's DNA. This mutated DNA can be passed to the next generation and
4521-492: Is especially relevant for choosing between competing theories. So in the case above, evidence plays the role of neutral arbiter between Newton's and Einstein's theory of gravitation. This is only possible if scientific evidence is public and uncontroversial so that proponents of competing scientific theories agree on what evidence is available. These requirements suggest scientific evidence consists not of private mental states but of public physical objects or events . It
4658-433: Is found in a cDNA library . PCR has many variations, like reverse transcription PCR ( RT-PCR ) for amplification of RNA, and, more recently, quantitative PCR which allow for quantitative measurement of DNA or RNA molecules. Gel electrophoresis is a technique which separates molecules by their size using an agarose or polyacrylamide gel. This technique is one of the principal tools of molecular biology. The basic principle
4795-446: Is infeasible, some of the benefits of consilience may still be obtained if it is well-established that these techniques usually give the same result. Consilience is important across all of science, including the social sciences, and is often used as an argument for scientific realism by philosophers of science. Each branch of science studies a subset of reality that depends on factors studied in other branches. Atomic physics underlies
4932-454: Is known as horizontal gene transfer (HGT). This phenomenon is now referred to as genetic transformation. Griffith's experiment addressed the pneumococcus bacteria, which had two different strains, one virulent and smooth and one avirulent and rough. The smooth strain had glistering appearance owing to the presence of a type of specific polysaccharide – a polymer of glucose and glucuronic acid capsule. Due to this polysaccharide layer of bacteria,
5069-446: Is more dominant in the philosophy of science, focuses on evidence as that which confirms scientific hypotheses and arbitrates between competing theories. On this view, it is essential that evidence is public so that different scientists can share the same evidence. This leaves publicly observable phenomena like physical objects and events as the best candidates for evidence, unlike private mental states. One problem with these approaches
5206-402: Is no lawful connection between this one nickel and the other coins in the pocket. Hypothetico-deductivism is a non-probabilistic approach that characterizes the evidential relations in terms of deductive consequences of the hypothesis. According to this view, "evidence for a hypothesis is a true observational consequence of that hypothesis". One problem with the characterization so far
5343-472: Is now inside a cell, and the protein can now be expressed. A variety of systems, such as inducible promoters and specific cell-signaling factors, are available to help express the protein of interest at high levels. Large quantities of a protein can then be extracted from the bacterial or eukaryotic cell. The protein can be tested for enzymatic activity under a variety of situations, the protein may be crystallized so its tertiary structure can be studied, or, in
5480-456: Is occurring by measuring how much of that RNA is present in different samples, assuming that no post-transcriptional regulation occurs and that the levels of mRNA reflect proportional levels of the corresponding protein being produced. It is one of the most basic tools for determining at what time, and under what conditions, certain genes are expressed in living tissues. A western blot is a technique by which specific proteins can be detected from
5617-478: Is often combined with the idea that evidence, propositional or otherwise, determines what it is rational for us to believe. But it can be rational to have a false belief. This is the case when we possess misleading evidence. For example, it was rational for Neo in the Matrix movie to believe that he was living in the 20th century because of all the evidence supporting his belief despite the fact that this evidence
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5754-534: Is often held as an argument against this view since sensory impressions are commonly treated as evidence. Propositionalism is sometimes combined with the view that only attitudes to true propositions can count as evidence. On this view, the belief that the corner shop sells milk only constitutes evidence for the belief that the corner shop sells dairy products if the corner shop actually sells milk. Against this position, it has been argued that evidence can be misleading but still count as evidence. This line of thought
5891-411: Is often held that evidence is in some sense prior to the hypotheses it confirms. This was sometimes understood as temporal priority , i.e. that we come first to possess the evidence and later form the hypothesis through induction. But this temporal order is not always reflected in scientific practice, where experimental researchers may look for a specific piece of evidence in order to confirm or disconfirm
6028-426: Is sometimes held that only propositional mental states can play this role, a position known as "propositionalism". A mental state is propositional if it is an attitude directed at a propositional content. Such attitudes are usually expressed by verbs like "believe" together with a that-clause, as in "Robert believes that the corner shop sells milk". Such a view denies that sensory impressions can act as evidence. This
6165-495: Is strong evidence in favor of that event occurring even if each individual historian is only partially reliable. By contrast, if the same historian had made the same claim five times in five different places (and no other types of evidence were available), the claim is much weaker because it originates from a single source. The evidence from the ancient historians could also converge with evidence from other fields, such as archaeology: for example, evidence that many senators fled Rome at
6302-419: Is strong evidence that none of the methods are in error and the conclusion is correct. This is because of a greatly reduced likelihood of errors: for a consensus estimate from multiple measurements to be wrong, the errors would have to be similar for all samples and all methods of measurement, which is extremely unlikely. Random errors will tend to cancel out as more measurements are made, due to regression to
6439-493: Is supported by a convergence of evidence: if not, the evidence is comparatively weak, and there will probably not be a strong scientific consensus . The principle is based on unity of knowledge ; measuring the same result by several different methods should lead to the same answer. For example, it should not matter whether one measures distances within the Giza pyramid complex by laser rangefinding , by satellite imaging , or with
6576-484: Is susceptible to influence by strong alkaline buffering agents, such as sodium dodecyl sulfate (SDS). The terms northern , western and eastern blotting are derived from what initially was a molecular biology joke that played on the term Southern blotting , after the technique described by Edwin Southern for the hybridisation of blotted DNA. Patricia Thomas, developer of the RNA blot which then became known as
6713-400: Is that DNA fragments can be separated by applying an electric current across the gel - because the DNA backbone contains negatively charged phosphate groups, the DNA will migrate through the agarose gel towards the positive end of the current. Proteins can also be separated on the basis of size using an SDS-PAGE gel, or on the basis of size and their electric charge by using what is known as
6850-403: Is that hypotheses usually contain relatively little information and therefore have few if any deductive observational consequences. So the hypothesis by itself that there is a fire does not entail that smoke is observed. Instead, various auxiliary assumptions have to be included about the location of the smoke, the fire, the observer, the lighting conditions, the laws of chemistry, etc. In this way,
6987-402: Is that justified belief has to be connected to or grounded in the mental state acting as its evidence. So Phoebe's belief that the speakers are on is not justified by her auditory experience if the belief is not based in this experience. This would be the case, for example, if Phoebe has both the experience and the belief but is unaware of the fact that the music is produced by the speakers. It
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#17327910276837124-437: Is that the resulting definitions of evidence, both within a field and between fields, vary a lot and are incompatible with each other. For example, it is not clear what a bloody knife and a perceptual experience have in common when both are treated as evidence in different disciplines. This suggests that there is no unitary concept corresponding to the different theoretical roles ascribed to evidence, i.e. that we do not always mean
7261-532: Is that this priority is epistemic in nature, i.e. that our belief in a hypothesis is justified based on the evidence while the justification for the belief in the evidence does not depend on the hypothesis. A central issue for the scientific conception of evidence is the problem of underdetermination , i.e. that the evidence available supports competing theories equally well. So, for example, evidence from our everyday life about how gravity works confirms Newton's and Einstein's theory of gravitation equally well and
7398-415: Is the hypothesis rejected: this can be referred to as ' refutation of the hypothesis'. The rules for evidence used by science are collected systematically in an attempt to avoid the bias inherent to anecdotal evidence . In law, the production and presentation of evidence depend first on establishing on whom the burden of proof lies. Admissible evidence is that which a court receives and considers for
7535-412: Is then exposed to a labeled DNA probe that has a complement base sequence to the sequence on the DNA of interest. Southern blotting is less commonly used in laboratory science due to the capacity of other techniques, such as PCR , to detect specific DNA sequences from DNA samples. These blots are still used for some applications, however, such as measuring transgene copy number in transgenic mice or in
7672-420: Is therefore unable to establish consensus among scientists. But in such cases, it is often the gradual accumulation of evidence that eventually leads to an emerging consensus. This evidence-driven process towards consensus seems to be one hallmark of the sciences not shared by other fields. Another problem for the conception of evidence in terms of confirmation of hypotheses is that what some scientists consider
7809-520: Is used to detect post-translational modification of proteins. Proteins blotted on to the PVDF or nitrocellulose membrane are probed for modifications using specific substrates. A DNA microarray is a collection of spots attached to a solid support such as a microscope slide where each spot contains one or more single-stranded DNA oligonucleotide fragments. Arrays make it possible to put down large quantities of very small (100 micrometre diameter) spots on
7946-499: Is why evidence is often associated with the controversial thesis that it constitutes an immediate access to truth. In this sense, the evidently given phenomenon guarantees its own truth and is therefore considered indubitable. Due to this special epistemological status of evidence, it is regarded in phenomenology as the basic principle of all philosophy. In this form, it represents the lowest foundation of knowledge, which consists of indubitable insights upon which all subsequent knowledge
8083-565: The Medical Research Council Unit, Cavendish Laboratory , were the first to describe the double helix model for the chemical structure of deoxyribonucleic acid (DNA), which is often considered a landmark event for the nascent field because it provided a physico-chemical basis by which to understand the previously nebulous idea of nucleic acids as the primary substance of biological inheritance. They proposed this structure based on previous research done by Franklin, which
8220-589: The Renaissance and found its apogee in the Age of Enlightenment . Whewell's definition was that: The Consilience of Inductions takes place when an Induction , obtained from one class of facts, coincides with an Induction obtained from another different class. Thus Consilience is a test of the truth of the Theory in which it occurs. More recent descriptions include: "Where there is a convergence of evidence, where
8357-425: The genetic code is a triplet code, where each triplet (called a codon ) specifies a particular amino acid. Furthermore, it was shown that the codons do not overlap with each other in the DNA sequence encoding a protein, and that each sequence is read from a fixed starting point. During 1962–1964, through the use of conditional lethal mutants of a bacterial virus, fundamental advances were made in our understanding of
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#17327910276838494-506: The logical positivists , Timothy Williamson , Earl Conee and Richard Feldman. Russell, Quine and the logical positivists belong to the empiricist tradition and hold that evidence consists in sense data, stimulation of one's sensory receptors and observation statements, respectively. According to Williamson, all and only knowledge constitute evidence. Conee and Feldman hold that only one's current mental states should be considered evidence. The guiding intuition within epistemology concerning
8631-422: The northern blot , actually did not use the term. Named after its inventor, biologist Edwin Southern , the Southern blot is a method for probing for the presence of a specific DNA sequence within a DNA sample. DNA samples before or after restriction enzyme (restriction endonuclease) digestion are separated by gel electrophoresis and then transferred to a membrane by blotting via capillary action . The membrane
8768-438: The probability of the supported statement. According to hypothetico-deductivism , evidence consists in observational consequences of a hypothesis. The positive-instance approach states that an observation sentence is evidence for a universal statement if the sentence describes a positive instance of this statement. Understood in its broadest sense, evidence for a proposition is what supports this proposition. Traditionally,
8905-422: The strength of evidence for any particular conclusion is related to how many independent methods are supporting the conclusion, as well as how different these methods are. Those techniques with the fewest (or no) shared characteristics provide the strongest consilience and result in the strongest conclusions. This also means that confidence is usually strongest when considering evidence from different fields because
9042-476: The 18th century, a detailed understanding of the mechanisms and interactions governing their behavior did not emerge until the 20th century, when technologies used in physics and chemistry had advanced sufficiently to permit their application in the biological sciences. The term 'molecular biology' was first used in 1945 by the English physicist William Astbury , who described it as an approach focused on discerning
9179-640: The Bradford assay can then be measured using a visible light spectrophotometer , and therefore does not require extensive equipment. This method was developed in 1975 by Marion M. Bradford , and has enabled significantly faster, more accurate protein quantitation compared to previous methods: the Lowry procedure and the biuret assay. Unlike the previous methods, the Bradford assay is not susceptible to interference by several non-protein molecules, including ethanol, sodium chloride, and magnesium chloride. However, it
9316-461: The DNA model was Phoebus Levene , who proposed the "polynucleotide model" of DNA in 1919 as a result of his biochemical experiments on yeast. In 1950, Erwin Chargaff expanded on the work of Levene and elucidated a few critical properties of nucleic acids: first, the sequence of nucleic acids varies across species. Second, the total concentration of purines (adenine and guanine) is always equal to
9453-486: The Holocaust. We must examine the collective whole." That is, individually the evidence may underdetermine the conclusion, but together they overdetermine it. A similar way to state this is that to ask for one particular piece of evidence in favor of a conclusion is a flawed question. In addition to the sciences, consilience can be important to the arts , ethics and religion. Both artists and scientists have identified
9590-484: The Scientific Revolution (1959). Wilson believed that "the humanities, ranging from philosophy and history to moral reasoning, comparative religion, and interpretation of the arts, will draw closer to the sciences and partly fuse with them" with the result that science and the scientific method, from within this fusion, would not only explain the physical phenomenon but also provide moral guidance and be
9727-437: The array and visualization of the hybridization can be done. Since multiple arrays can be made with exactly the same position of fragments, they are particularly useful for comparing the gene expression of two different tissues, such as a healthy and cancerous tissue. Also, one can measure what genes are expressed and how that expression changes with time or with other factors. There are many different ways to fabricate microarrays;
9864-473: The atomic level. Molecular biologists today have access to increasingly affordable sequencing data at increasingly higher depths, facilitating the development of novel genetic manipulation methods in new non-model organisms. Likewise, synthetic molecular biologists will drive the industrial production of small and macro molecules through the introduction of exogenous metabolic pathways in various prokaryotic and eukaryotic cell lines. Horizontally, sequencing data
10001-403: The bacteriophage's protein coat with radioactive sulphur and DNA with radioactive phosphorus, into two different test tubes respectively. After mixing bacteriophage and E.coli into the test tube, the incubation period starts in which phage transforms the genetic material in the E.coli cells. Then the mixture is blended or agitated, which separates the phage from E.coli cells. The whole mixture
10138-412: The burden resting on presenters of a paper, in which the presenters argue for their specific findings. This paper is placed before a panel of judges where the presenter must defend the thesis against all challenges. When evidence is contradictory to predicted expectations, the evidence and the ways of making it are often closely scrutinized (see experimenter's regress ) and only at the end of this process
10275-566: The concept of consilience in Whewell's sense was widely discussed by philosophers of science, the term was unfamiliar to the broader public until the end of the 20th century, when it was revived in Consilience: The Unity of Knowledge , a 1998 book by the author and biologist E. O. Wilson , as an attempt to bridge the cultural gap between the sciences and the humanities that was the subject of C. P. Snow 's The Two Cultures and
10412-409: The conditional probability of this hypothesis relative to the evidence is higher than the unconditional probability of the hypothesis by itself. Smoke (E), for example, is evidence that there is a fire (H), because the two usually occur together, which is why the likelihood of fire given that there is smoke is higher than the likelihood of fire by itself. On this view, evidence is akin to an indicator or
10549-493: The development of new technologies and their optimization. Molecular biology has been elucidated by the work of many scientists, and thus the history of the field depends on an understanding of these scientists and their experiments. The field of genetics arose from attempts to understand the set of rules underlying reproduction and heredity , and the nature of the hypothetical units of heredity known as genes . Gregor Mendel pioneered this work in 1866, when he first described
10686-399: The domain "{a}", containing only the one individual mentioned in the evidence, entails the evidence, i.e. " s w a n ( a ) ∧ w h i t e ( a ) {\displaystyle swan(a)\land white(a)} " (this swan is white). One important shortcoming of this approach is that it requires that the hypothesis and the evidence are formulated in
10823-401: The engineering of gene knockout embryonic stem cell lines . The northern blot is used to study the presence of specific RNA molecules as relative comparison among a set of different samples of RNA. It is essentially a combination of denaturing RNA gel electrophoresis , and a blot . In this process RNA is separated based on size and is then transferred to a membrane that is then probed with
10960-455: The evidence to be may already involve various theoretical assumptions not shared by other scientists. This phenomenon is known as theory-ladenness . Some cases of theory-ladenness are relatively uncontroversial, for example, that the numbers output by a measurement device need additional assumptions about how this device works and what was measured in order to count as meaningful evidence. Other putative cases are more controversial, for example,
11097-409: The evidence, considered together as a whole, results in the strong scientific consensus that the theory is correct. In a similar way, evidence about the history of the universe is drawn from astronomy, astrophysics, planetary geology, and physics. Finding similar conclusions from multiple independent methods is also evidence for the reliability of the methods themselves, because consilience eliminates
11234-518: The evidential relation becomes a three-place relation between evidence, hypothesis and auxiliary assumptions. This means that whether a thing is evidence for a hypothesis depends on the auxiliary assumptions one holds. This approach fits well with various scientific practices. For example, it is often the case that experimental scientists try to find evidence that would confirm or disconfirm a proposed theory. The hypothetico-deductive approach can be used to predict what should be observed in an experiment if
11371-409: The evidential relation in terms of probabilities. They hold that all that is necessary is that the existence of the evidence increases the likelihood that the hypothesis is true. This can be expressed mathematically as P ( H ∣ E ) > P ( H ) {\displaystyle P(H\mid E)>P(H)} . In words: a piece of evidence (E) confirms a hypothesis (H) if
11508-412: The experiment involved growing E. coli bacteria in a medium containing heavy isotope of nitrogen ( N) for several generations. This caused all the newly synthesized bacterial DNA to be incorporated with the heavy isotope. After allowing the bacteria to replicate in a medium containing normal nitrogen ( N), samples were taken at various time points. These samples were then subjected to centrifugation in
11645-399: The extract. They discovered that when they digested the DNA in the extract with DNase , transformation of harmless bacteria into virulent ones was lost. This provided strong evidence that DNA was the genetic material, challenging the prevailing belief that proteins were responsible. It laid the basis for the subsequent discovery of its structure by Watson and Crick. Confirmation that DNA is
11782-432: The fact that Socrates's wisdom is irrelevant here. According to the positive-instance approach , an observation sentence is evidence for a universal hypothesis if the sentence describes a positive instance of this hypothesis. For example, the observation that "this swan is white" is an instance of the universal hypothesis that "all swans are white". This approach can be given a precise formulation in first-order logic :
11919-449: The fact that even among phenomenologists, there is much disagreement about the basic structures of experience. In the sciences, evidence is understood as what confirms or disconfirms scientific hypotheses . The term "confirmation" is sometimes used synonymously with that of "evidential support". Measurements of Mercury's "anomalous" orbit, for example, are seen as evidence that confirms Einstein's theory of general relativity. This
12056-403: The former requiring evidence beyond a reasonable doubt , the latter considering only which side has the preponderance of evidence , or whether the proposition is more likely true or false. The parts of a legal case that are not in controversy are known, in general, as the "facts of the case." Beyond any facts that are undisputed, a judge or jury is usually tasked with being a trier of fact for
12193-504: The functions and interactions of the proteins employed in the machinery of DNA replication , DNA repair , DNA recombination , and in the assembly of molecular structures. In 1928, Frederick Griffith , encountered a virulence property in pneumococcus bacteria, which was killing lab rats. According to Mendel, prevalent at that time, gene transfer could occur only from parent to daughter cells. Griffith advanced another theory, stating that gene transfer occurring in member of same generation
12330-526: The genetic material which is cause of infection came from the Hershey–Chase experiment . They used E.coli and bacteriophage for the experiment. This experiment is also known as blender experiment, as kitchen blender was used as a major piece of apparatus. Alfred Hershey and Martha Chase demonstrated that the DNA injected by a phage particle into a bacterium contains all information required to synthesize progeny phage particles. They used radioactivity to tag
12467-402: The idea that different people or cultures perceive the world through different, incommensurable conceptual schemes , leading them to very different impressions about what is the case and what evidence is available. Theory-ladenness threatens to impede the role of evidence as neutral arbiter since these additional assumptions may favor some theories over others. It could thereby also undermine
12604-402: The implausible consequence that many of simple everyday-beliefs would be unjustified. The more common view is that all kinds of mental states, including stored beliefs that are currently unconscious, can act as evidence. It is sometimes argued that the possession of a mental state capable of justifying another is not sufficient for the justification to happen. The idea behind this line of thought
12741-522: The implications of this unique structure for possible mechanisms of DNA replication. Watson and Crick were awarded the Nobel Prize in Physiology or Medicine in 1962, along with Wilkins, for proposing a model of the structure of DNA. In 1961, it was demonstrated that when a gene encodes a protein , three sequential bases of a gene's DNA specify each successive amino acid of the protein. Thus
12878-464: The importance of biology in the process of artistic innovation. Consilience has its roots in the ancient Greek concept of an intrinsic orderliness that governs our cosmos , inherently comprehensible by logical process, a vision at odds with mystical views in many cultures that surrounded the Hellenes. The rational view was recovered during the high Middle Ages , separated from theology during
13015-434: The laws of inheritance he observed in his studies of mating crosses in pea plants. One such law of genetic inheritance is the law of segregation , which states that diploid individuals with two alleles for a particular gene will pass one of these alleles to their offspring. Because of his critical work, the study of genetic inheritance is commonly referred to as Mendelian genetics . A major milestone in molecular biology
13152-410: The mean ; systematic errors will be detected by differences between the measurements and will also tend to cancel out since the direction of the error will still be random. This is how scientific theories reach high confidence—over time, they build up a large degree of evidence which converges on the same conclusion. When results from different strong methods do appear to conflict, this is treated as
13289-418: The methods are independent, when one of several methods is in error, it is very unlikely to be in error in the same way as any of the other methods, and a difference between the measurements will be observed. If the scientific understanding of the properties of lasers was inaccurate, then the laser measurement would be inaccurate but the others would not. As a result, when several different methods agree, this
13426-496: The more these characteristics will be present. There are six intrinsic characteristics of evidence: In addition, four subjective or external characteristics can be detected over those things that are more or less evident: These ten characteristics of what is evident allowed Riofrio to formulate a test of evidence to detect the level of certainty or evidence that one argument or proof could have. Important theorists of evidence include Bertrand Russell , Willard Van Orman Quine ,
13563-415: The most common are silicon chips, microscope slides with spots of ~100 micrometre diameter, custom arrays, and arrays with larger spots on porous membranes (macroarrays). There can be anywhere from 100 spots to more than 10,000 on a given array. Arrays can also be made with molecules other than DNA. Allele-specific oligonucleotide (ASO) is a technique that allows detection of single base mutations without
13700-399: The need for PCR or gel electrophoresis. Short (20–25 nucleotides in length), labeled probes are exposed to the non-fragmented target DNA, hybridization occurs with high specificity due to the short length of the probes and even a single base change will hinder hybridization. The target DNA is then washed and the unhybridized probes are removed. The target DNA is then analyzed for the presence of
13837-425: The new result, the weight of evidence will still favor the established result. This means that the new evidence is most likely to be wrong. Science denialism (for example, AIDS denialism ) is often based on a misunderstanding of this property of consilience. A denier may promote small gaps not yet accounted for by the consilient evidence, or small amounts of evidence contradicting a conclusion without accounting for
13974-400: The other issues of a case. Evidence and rules are used to decide questions of fact that are disputed, some of which may be determined by the legal burden of proof relevant to the case. Evidence in certain cases (e.g. capital crimes ) must be more compelling than in other situations (e.g. minor civil disputes), which drastically affects the quality and quantity of evidence necessary to decide
14111-462: The overall burden of proof is on the side supporting the resolution. Molecular biology Molecular biology / m ə ˈ l ɛ k j ʊ l ər / is a branch of biology that seeks to understand the molecular basis of biological activity in and between cells , including biomolecular synthesis, modification, mechanisms, and interactions. Though cells and other microscopic structures had been observed in living organisms as early as
14248-463: The pharmaceutical industry, the activity of new drugs against the protein can be studied. Polymerase chain reaction (PCR) is an extremely versatile technique for copying DNA. In brief, PCR allows a specific DNA sequence to be copied or modified in predetermined ways. The reaction is extremely powerful and under perfect conditions could amplify one DNA molecule to become 1.07 billion molecules in less than two hours. PCR has many applications, including
14385-444: The possibility of all potential errors that do not affect all the methods equally. This is also used for the validation of new techniques through comparison with the consilient ones. If only partial consilience is observed, this allows for the detection of errors in methodology; any weaknesses in one technique can be compensated for by the strengths of the others. Alternatively, if using more than one or two techniques for every experiment
14522-599: The pre-existing strength resulting from consilience. More generally, to insist that all evidence converge precisely with no deviations would be naïve falsificationism, equivalent to considering a single contrary result to falsify a theory when another explanation, such as equipment malfunction or misinterpretation of results, is much more likely. Historical evidence also converges in an analogous way. For example: if five ancient historians, none of whom knew each other, all claim that Julius Caesar seized power in Rome in 49 BCE, this
14659-405: The probe via radioactivity or fluorescence. In this experiment, as in most molecular biology techniques, a control must be used to ensure successful experimentation. In molecular biology, procedures and technologies are continually being developed and older technologies abandoned. For example, before the advent of DNA gel electrophoresis ( agarose or polyacrylamide ), the size of DNA molecules
14796-530: The protein of interest can then be visualized by a variety of techniques, including colored products, chemiluminescence , or autoradiography . Often, the antibodies are labeled with enzymes. When a chemiluminescent substrate is exposed to the enzyme it allows detection. Using western blotting techniques allows not only detection but also quantitative analysis. Analogous methods to western blotting can be used to directly stain specific proteins in live cells or tissue sections. The eastern blotting technique
14933-465: The purposes of deciding a particular case. Two primary burden-of-proof considerations exist in law. The first is on whom the burden rests. In many, especially Western, courts, the burden of proof is placed on the prosecution in criminal cases and the plaintiff in civil cases. The second consideration is the degree of certitude proof must reach, depending on both the quantity and quality of evidence. These degrees are different for criminal and civil cases,
15070-479: The relation between evidence and the proposition supported by it. The issue of the nature of the evidential relation concerns the question of what this relation has to be like in order for one thing to justify a belief or to confirm a hypothesis. Important theories in this field include the probabilistic approach , hypothetico-deductivism and the positive-instance approach . Probabilistic approaches , also referred to as Bayesian confirmation theory , explain
15207-459: The role of evidence is that it is what justifies beliefs . For example, Phoebe's auditory experience of the music justifies her belief that the speakers are on. Evidence has to be possessed by the believer in order to play this role. So Phoebe's own experiences can justify her own beliefs but not someone else's beliefs. Some philosophers hold that evidence possession is restricted to conscious mental states, for example, to sense data. This view has
15344-481: The role of scientific evidence. In law , evidence is information to establish or refute claims relevant to a case, such as testimony , documentary evidence , and physical evidence . The relation between evidence and a supported statement can vary in strength, ranging from weak correlation to indisputable proof . Theories of the evidential relation examine the nature of this connection. Probabilistic approaches hold that something counts as evidence if it increases
15481-417: The same explanation is implied, there is increased confidence in the explanation. Where there is divergence, then either the explanation is at fault or one or more of the sources of information is in error or requires reinterpretation." "Proof is derived through a convergence of evidence from numerous lines of inquiry--multiple, independent inductions, all of which point to an unmistakable conclusion." Although
15618-510: The same thing when we talk of evidence. On the other hand, Aristotle, phenomenologists, and numerous scholars accept that there could be several degrees of evidence. For instance, while the outcome of a complex equation may become more or less evident to a mathematician after hours of deduction, yet with little doubts about it, a simpler formula would appear more evident to them. Riofrio has detected some characteristics that are present in evident arguments and proofs. The more they are evident,
15755-430: The same vocabulary, i.e. use the same predicates, like " s w a n {\displaystyle swan} " or " w h i t e {\displaystyle white} " above. But many scientific theories posit theoretical objects, like electrons or strings in physics, that are not directly observable and therefore cannot show up in the evidence as conceived here. In scientific research evidence
15892-421: The study of gene expression, the detection of pathogenic microorganisms, the detection of genetic mutations, and the introduction of mutations to DNA. The PCR technique can be used to introduce restriction enzyme sites to ends of DNA molecules, or to mutate particular bases of DNA, the latter is a method referred to as site-directed mutagenesis . PCR can also be used to determine whether a particular DNA fragment
16029-532: The study of gene structure and function, has been among the most prominent sub-fields of molecular biology since the early 2000s. Other branches of biology are informed by molecular biology, by either directly studying the interactions of molecules in their own right such as in cell biology and developmental biology , or indirectly, where molecular techniques are used to infer historical attributes of populations or species , as in fields in evolutionary biology such as population genetics and phylogenetics . There
16166-554: The synthesis of a new complementary strand, resulting in two daughter DNA molecules, each consisting of one parental and one newly synthesized strand. The Meselson-Stahl experiment provided compelling evidence for the semiconservative replication of DNA, which is fundamental to the understanding of genetics and molecular biology. In the early 2020s, molecular biology entered a golden age defined by both vertical and horizontal technical development. Vertically, novel technologies are allowing for real-time monitoring of biological processes at
16303-527: The techniques are usually very different. For example, the theory of evolution is supported by a convergence of evidence from genetics , molecular biology , paleontology , geology, biogeography , comparative anatomy , comparative physiology , and many other fields. In fact, the evidence within each of these fields is itself a convergence providing evidence for the theory. As a result, to disprove evolution, most or all of these independent lines of evidence would have to be found to be in error. The strength of
16440-411: The term universology , which literally means "the science of the universe." Universology was first promoted for the study of the interconnecting principles and truths of all domains of knowledge by Stephen Pearl Andrews , a 19th-century utopian futurist and anarchist. Evidence In the philosophy of science , evidence is material that confirms or disconfirms scientific hypotheses , acting as
16577-403: The term "evidence" in phenomenology shows many parallels to its epistemological usage, but it is understood in a narrower sense. Thus, evidence here specifically refers to intuitive knowledge, which is described as "self-given" ( selbst-gegeben ). This contrasts with empty intentions, in which one refers to states of affairs through a certain opinion, but without an intuitive presentation. This
16714-405: The term is sometimes understood in a narrower sense: as the intuitive knowledge of facts that are considered indubitable. In this sense, only the singular form is used. This meaning is found especially in phenomenology, in which evidence is elevated to one of the basic principles of philosophy, giving philosophy the ultimate justifications that are supposed to turn it into a rigorous science. In
16851-486: The theory of Transduction came into existence. Transduction is a process in which the bacterial DNA carry the fragment of bacteriophages and pass it on the next generation. This is also a type of horizontal gene transfer. The Meselson-Stahl experiment was a landmark experiment in molecular biology that provided evidence for the semiconservative replication of DNA. Conducted in 1958 by Matthew Meselson and Franklin Stahl ,
16988-402: The theory was true. It thereby explains the evidential relation between the experiment and the theory. One problem with this approach is that it cannot distinguish between relevant and certain irrelevant cases. So if smoke is evidence for the hypothesis "there is fire", then it is also evidence for conjunctions including this hypothesis, for example, "there is fire and Socrates was wise", despite
17125-466: The time, that the battles of Caesar’s civil war occurred, and so forth. Consilience has also been discussed in reference to Holocaust denial . "We [have now discussed] eighteen proofs all converging on one conclusion...the deniers shift the burden of proof to historians by demanding that each piece of evidence, independently and without corroboration between them, prove the Holocaust. Yet no historian has ever claimed that one piece of evidence proves
17262-451: The total concentration of pyrimidines (cysteine and thymine). This is now known as Chargaff's rule. In 1953, James Watson and Francis Crick published the double helical structure of DNA, based on the X-ray crystallography work done by Rosalind Franklin which was conveyed to them by Maurice Wilkins and Max Perutz . Watson and Crick described the structure of DNA and conjectured about
17399-618: The two main categories of evidence presented at a trial or hearing. In the United States, evidence in federal court is admitted or excluded under the Federal Rules of Evidence . The burden of proof is the obligation of a party in an argument or dispute to provide sufficient evidence to shift the other party's or a third party's belief from their initial position. The burden of proof must be fulfilled by both establishing confirming evidence and negating oppositional evidence. Conclusions drawn from evidence may be subject to criticism based on
17536-428: The ultimate source of all truths. Wilson held that with the rise of the modern sciences , the sense of unity gradually was lost in the increasing fragmentation and specialization of knowledge in the last two centuries. He asserted that the sciences, humanities, and arts have a common goal: to give a purpose to understand the details, to lend to all inquirers "a conviction, far deeper than a mere working proposition, that
17673-448: The underpinnings of biological phenomena—i.e. uncovering the physical and chemical structures and properties of biological molecules, as well as their interactions with other molecules and how these interactions explain observations of so-called classical biology, which instead studies biological processes at larger scales and higher levels of organization. In 1953, Francis Crick , James Watson , Rosalind Franklin , and their colleagues at
17810-437: The use of independent methods of measurement, meaning that the methods have few shared characteristics. That is, the mechanism by which the measurement is made is different; each method is dependent on an unrelated natural phenomenon. For example, the accuracy of laser range-finding measurements is based on the scientific understanding of lasers , while satellite pictures and meter (yard-)sticks rely on different phenomena. Because
17947-443: The use of molecular biology or molecular cell biology in medicine is now referred to as molecular medicine . Molecular biology sits at the intersection of biochemistry and genetics ; as these scientific disciplines emerged and evolved in the 20th century, it became clear that they both sought to determine the molecular mechanisms which underlie vital cellular functions. Advances in molecular biology have been closely related to
18084-460: The workings of chemistry , which studies emergent properties that in turn are the basis of biology . Psychology is not separate from the study of properties emergent from the interaction of neurons and synapses . Sociology, economics, and anthropology are each, in turn, studies of properties emergent from the interaction of countless individual humans. The concept that all the different areas of research are studying one real, existing universe
18221-480: The world is orderly and can be explained by a small number of natural laws." An important point made by Wilson is that hereditary human nature and evolution itself profoundly affect the evolution of culture, in essence, a sociobiological concept. Wilson's concept is a much broader notion of consilience than that of Whewell, who was merely pointing out that generalizations invented to account for one set of phenomena often account for others as well. A parallel view lies in
18358-474: Was a landmark study conducted in 1944 that demonstrated that DNA, not protein as previously thought, carries genetic information in bacteria. Oswald Avery , Colin Munro MacLeod , and Maclyn McCarty used an extract from a strain of pneumococcus that could cause pneumonia in mice. They showed that genetic transformation in the bacteria could be accomplished by injecting them with purified DNA from
18495-495: Was conveyed to them by Maurice Wilkins and Max Perutz . Their work led to the discovery of DNA in other microorganisms, plants, and animals. The field of molecular biology includes techniques which enable scientists to learn about molecular processes. These techniques are used to efficiently target new drugs, diagnose disease, and better understand cell physiology. Some clinical research and medical therapies arising from molecular biology are covered under gene therapy , whereas
18632-460: Was misleading since it was part of a simulated reality. This account of evidence and rationality can also be extended to other doxastic attitudes, like disbelief and suspension of belief. So rationality does not just demand that we believe something if we have decisive evidence for it, it also demands that we disbelieve something if we have decisive evidence against it and that we suspend belief if we lack decisive evidence either way. The meaning of
18769-414: Was the discovery of the structure of DNA . This work began in 1869 by Friedrich Miescher , a Swiss biochemist who first proposed a structure called nuclein , which we now know to be (deoxyribonucleic acid), or DNA. He discovered this unique substance by studying the components of pus-filled bandages, and noting the unique properties of the "phosphorus-containing substances". Another notable contributor to
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