lunes, 29 de octubre de 2007

On Evidence

Evidence are a group of events that support or not a hypotesis. A pure observation not must be considered as evidence, a pure observation (observations are not bounded to theorical basis) is not evidence. The evidence's quality is related to hypotesis which it is bounded. So, all evidence is not relevant for a hypotesis. Evidence is not considered as “good” or “bad”, simply it is support a event rather other. The pure observations (without theoric basis) is considered “good” or “bad. So, in the historical sciences the observation of event is not enough, these observation must be bounded a theorical background. The “smoking gun” is a example which the evidence is obtained, but all the observations in the event ( murder) must be related to a theory. The observations that are not related to murder, it are not evidence.

domingo, 28 de octubre de 2007


A hypothesis is a conjecture, a speculation, a hunch, framed in such a way that it can be tested. The result from this test is accepted, until new evidence is available and regarded (Gee, 1999). But, testing a hypothesis requires that it makes a prediction that can be checked by observation, and we make observations in order to learn about things that we do not observe (Sober, 1999). Our observations, then goes far from the mere action of sensing an object, and that's why our observations are always full of theory. Although, when we test competing hypotheses we use the same tools for doing observations, and the theoretical machinery could be regarded as auxiliary hypotheses that do not alter the test result.

Cladistics, is a historical science, then it emphasis in analyzing and shapering traces at the light of a hypothesis (Cleland, 2002). In cladistic analysis a hypotheses is a presume relationship between taxa (a monophyletic group), and the evidence that 'corroborates' a group, are the synapomorphies (Patterson, 1988). But, at the beginning of the analysis there are not synapomorphies, just characters, observations that need a theoretical context. However, that a theoretical construct is necessary for evidence interpretation that is not an excuse for not seeing it with out bias about what it tells (i.e., adaptation, change sequence).

Because our hypotheses and methods always could be refined, and we would never have all the information any presumption is susceptible of being accepted or refuted in the light of new evidence.

On Evidence sensu CJ

The evidence consists of observations that are compatible with a hypothesis. These observations must be collected systematically in an attempt to avoid the bias inherent to observations that has been used as evidence in the past. In this sense what we call evidence depends on its informativeness regarding the hypothesis and is presumed to be true used in support of the hypotheses that are presumed to be falsifiable. Therefore the evidence goes toward supporting a hypothesis.

Cladistics or phylogenetic systematics groups organisms by their share derived characters. Taxa that share many derived characters are grouped more closely together than those that do not. Tree-like relationship diagrams called "cladograms" results showing hypothesized relationships. The evidence that organisms are related comes from homologies between them. The observable parts, or attributes, of organisms which can be examined for homology are characters. Therefore In these hypothesized relationships, the characters are considered the evidence.

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