The “four causes” are elements of an influential principle in Aristotelian thought whereby explanations of change or movement are classified into four fundamental types of answer to the question “why?”. Aristotle wrote that “we do not have knowledge of a thing until we have grasped its why, that is to say, its cause.” While there are cases where identifying a “cause” is difficult, or in which “causes” might merge, Aristotle held that his four “causes” provided an analytical scheme of general applicability.
Aitia, from Greek αἰτία, was the word that Aristotle used to refer to the causal explanation that has traditionally been translated as “cause”, but this peculiar specialized, technical, philosophical usage of the word “cause” does not correspond exactly to its most usual applications in everyday English language. The translation of Aristotle’s αἰτία that is nearest to current ordinary language could be “question” or “explanation”. In this article, the traditional philosophical usage of the word “cause” will be employed, but the reader should not be misled by confusing this technical usage with current ordinary language.
- Matter: a change or movement’s material cause is the aspect of the change or movement which is determined by the material that composes the moving or changing things. For a table, that might be wood; for a statue, that might be bronze or marble.
- Form: a change or movement’s formal cause is a change or movement caused by the arrangement, shape or appearance of the thing changing or moving. Aristotle says for example that the ratio 2:1, and number in general, is the cause of the octave.
- Agent: a change or movement’s efficient or moving cause consists of things apart from the thing being changed or moved, which interact so as to be an agency of the change or movement. For example, the efficient cause of a table is a carpenter, or a person working as one, and according to Aristotle the efficient cause of a boy is a father.
- End or purpose: a change or movement’s final cause is that for the sake of which a thing is what it is. For a seed, it might be an adult plant. For a sailboat, it might be sailing. For a ball at the top of a ramp, it might be coming to rest at the bottom.
The four “causes” are not mutually exclusive. For Aristotle, several answers to the question “why” have to be given to explain a phenomenon and especially the actual configuration of an object. For example, if asking why a table is such and such, a complete explanation, taking into account the four causes, would sound like this: This table is solid and brown because it is made of wood (matter), it does not collapse because it has four legs of equal length (form), it is as such because a carpenter made it starting from a tree (agent), it has these dimensions because it is to be used by men and women (end).
Causality (also referred to as causation, or cause and effect) is efficacy, by which one event, process or state, a cause, contributes to the production of another event, process or state, an effect, where the cause is partly responsible for the effect, and the effect is partly dependent on the cause. In general, a process has many causes, which are also said to be causal factors for it, and all lie in its past. An effect can in turn be a cause of, or causal factor for, many other effects, which all lie in its future. Some writers have held that causality is metaphysically prior to notions of time and space.
Causality is an abstraction that indicates how the world progresses, so basic a concept that it is more apt as an explanation of other concepts of progression than as something to be explained by others more basic. The concept is like those of agency and efficacy. For this reason, a leap of intuition may be needed to grasp it. Accordingly, causality is implicit in the logic and structure of ordinary language.
In the English language, as distinct from Aristotle’s own language, Aristotelian philosophy uses the word “cause” to mean “explanation” or “answer to a ‘why’ question”, including Aristotle‘s material, formal, efficient, and final “causes”; then the “cause” is the explanans for the explanandum. In this case, failure to recognize that different kinds of “cause” are being considered can lead to futile debate. Of Aristotle’s four explanatory modes, the one nearest to the concerns of the present article is the “efficient” one.
The topic of causality remains a staple in contemporary philosophy.
Necessary and sufficient causes
Causes may sometimes be distinguished into two types: necessary and sufficient. A third type of causation, which requires neither necessity nor sufficiency in and of itself, but which contributes to the effect, is called a “contributory cause.”
- Necessary causes
- If x is a necessary cause of y, then the presence of y necessarily implies the prior occurrence of x. The presence of x, however, does not imply that y will occur.
- Sufficient causes
- If x is a sufficient cause of y, then the presence of x necessarily implies the subsequent occurrence of y. However, another cause z may alternatively cause y. Thus the presence of y does not imply the prior occurrence of x.
- Contributory causes
- For some specific effect, in a singular case, a factor that is a contributory cause is one among several co-occurrent causes. It is implicit that all of them are contributory. For the specific effect, in general, there is no implication that a contributory cause is necessary, though it may be so. In general, a factor that is a contributory cause is not sufficient, because it is by definition accompanied by other causes, which would not count as causes if it were sufficient. For the specific effect, a factor that is on some occasions a contributory cause might on some other occasions be sufficient, but on those other occasions it would not be merely contributory.
J. L. Mackie argues that usual talk of “cause” in fact refers to INUS conditions (insufficient but non-redundant parts of a condition which is itself unnecessary but sufficient for the occurrence of the effect). An example is a short circuit as a cause for a house burning down. Consider the collection of events: the short circuit, the proximity of flammable material, and the absence of firefighters. Together these are unnecessary but sufficient to the house’s burning down (since many other collections of events certainly could have led to the house burning down, for example shooting the house with a flamethrower in the presence of oxygen and so forth). Within this collection, the short circuit is an insufficient (since the short circuit by itself would not have caused the fire) but non-redundant (because the fire would not have happened without it, everything else being equal) part of a condition which is itself unnecessary but sufficient for the occurrence of the effect. So, the short circuit is an INUS condition for the occurrence of the house burning down.
Chrysippus. Then being animate, you cannot be a stone.
Seventh Dealer. Ah! thank you, thank you. I was beginning to feel my limbs growing numb and solidifying like Niobe’s. Oh, I must have you. What’s to pay?
Hermes. Fifty pounds.
Patient to patient transmission of hepatitis B virus: a systematic review of reports on outbreaks between 1992 and 2007
BMC Medicine volume 7, Article number: 15 (2009)
Hepatitis B outbreaks in healthcare settings are still a serious public health concern in high-income countries. To elucidate the most frequent infection pathways and clinical settings involved, we performed a systematic review of hepatitis B virus outbreaks published between 1992 and 2007 within the EU and USA.
The research was performed using two different databases: the PubMed Database and the Outbreak Database, the worldwide database for nosocomial outbreaks. Selection of papers was carried out using the Quorom algorithm, and to avoid selection biases, the inclusion criteria were established before the articles were identified.
Overall, 30 papers were analyzed, reporting on 33 hepatitis B virus outbreaks that involved 471 patients, with 16 fatal cases. Dialysis units accounted for 30.3% of outbreaks followed by medical wards (21.2%), nursing homes (21.2%), surgery wards (15.2), and outpatient clinics (12.1%). The transmission pathways were: multi-vial drugs (30.3%), non-disposable multi-patient capillary blood sampling devices (27.2%), transvenous endomyocardial biopsy procedures (9.1%), and multiple deficiencies in applying standard precautions (9.1%).
The analysis of transmission pathways showed that some breaches in infection control measures, such as administration of drugs using multi-vial compounds and capillary blood sampling, are the most frequent routes for patient-to-patient transmission of hepatitis B virus. Moreover some outbreak reports underlined that heart-transplant recipients are at risk of contracting hepatitis B virus infection during the transvenous endomyocardial biopsy procedure through indirect contact with infected blood as a result of environmental contamination. To prevent transmission, healthcare workers must adhere to standard precautions and follow fundamental infection control principles, such as the use of sterile, single-use, disposable needles and avoiding the use of multi-vial compounds in all healthcare settings including outpatient settings.
Forty samples of air with a mean sample volume of 104 liters were collected during the treatment of patients whose blood was positive for HBsAG: no samples contained HBsAG and occult blood. These findings suggest that, if environmentally mediated transmission of hepatitis B occurs in the dental operatory, it is more likely to occur through contact with contaminated surfaces than through the airborne route.
Exosomes are vesicles of endocytic origin released by many cells. These vesicles can mediate communication between cells, facilitating processes such as antigen presentation. Here, we show that exosomes from a mouse and a human mast cell line (MC/9 and HMC-1, respectively), as well as primary bone marrow-derived mouse mast cells, contain RNA. Microarray assessments revealed the presence of mRNA from approximately 1300 genes, many of which are not present in the cytoplasm of the donor cell. In vitro translation proved that the exosome mRNAs were functional. Quality control RNA analysis of total RNA derived from exosomes also revealed presence of small RNAs, including microRNAs. The RNA from mast cell exosomes is transferable to other mouse and human mast cells. After transfer of mouse exosomal RNA to human mast cells, new mouse proteins were found in the recipient cells, indicating that transferred exosomal mRNA can be translated after entering another cell. In summary, we show that exosomes contain both mRNA and microRNA, which can be delivered to another cell, and can be functional in this new location. We propose that this RNA is called “exosomal shuttle RNA” (esRNA).
Cell Adh Migr. 2007 Jul-Sep;1(3):156-8. doi: 10.4161/cam.1.3.5114. Epub 2007 Jul 4.PMID: 19262134 Free PMC article. Review.
Expert Rev Proteomics. 2009 Jun;6(3):267-83. doi: 10.1586/epr.09.17.PMID: 19489699 Review.
J Extracell Vesicles. 2012 Apr 16;1. doi: 10.3402/jev.v1i0.18389. eCollection 2012.PMID: 24009880 Free PMC article.
PLoS One. 2010 Dec 17;5(12):e15353. doi: 10.1371/journal.pone.0015353.PMID: 21179422 Free PMC article.
Nat Struct Mol Biol. 2006 Dec;13(12):1102-7. doi: 10.1038/nsmb1174. Epub 2006 Nov 26.PMID: 17128271
IS AIDS MAN MADE?
“THE STRECKER MEMORANDUM DVD”
“Yeah. Maybe instead of three monkeys symbolizing denial, it should be three NCI virologists with their eyes, ears, and mouths covered.”
The Human Laboratory
Tonight’s programme investigates controversial contraceptive research carried out on women in Third World countries. It features testimony from women in the slums and villages of Bangladesh and Haiti, examines the belief of some Filipino women that they have been used as guinea pigs, and asks whether Third World testing of contraceptives can be unscientific and unethical. This pre-watershed programme deals with the emotive issue of family planning and its effect on women.
Written and produced by Deborah Cad bury
Editor John Lynch t See This Week: page 10
Editor: John Lynch
- sorites A kind of sophism invented by Chrysippus in the third century before Christ, by which a parson is led by gradual steps from maintaining what is manifestly true to admitting what is manifestly false. For example: One grain of sand cannot make a heap; then, if one grain be added to a grain, the one added grain cannot make that a heap which was not a heap before; and so on, until it is shown that a million or more grains of sand cannot make a heap.
- n sorites A chain-syllogism, or argument having a number of premises and one conclusion, the argumentation being capable of analysis into a number of syllogisms, the conclusion of each of which is a premise of the next. A sorites may be categorical or hypothetical, like a syllogism, and either variety may be progressive or regressive.
- n Sorites sō-rī′tēz an argument composed of an indeterminate number of propositions, so arranged that the predicate of the first becomes the subject of the second, and so on till the conclusion is reached, which unites the subject of the first with the predicate of the last.