Introduction to Forensic Investigations
Locard’s Exchange Principle and the use of Fingerprints:
Edmond Locard (1877-1966) was a French scientist specialised in both medicine and law. Inspired by the work of Hans Gross, it was Edmond that created the concept that all objects of any material should leave traces of itself upon whatever it touches, even if it is the minutest amount, simply put as “Every Contact leaves a trace,” Locard (1923). This is commonly known as Locard’s Exchange Principle. He believed that in circumstances such as a crime, his principle could be used to find evidence of who and perhaps even how that crime was committed by finding small materials, either physical or chemical at the scene of the crime that would directly link back to the offender.
Fingerprints are a classic example of what could be left by an offender at the scene of a crime that could prove he or she was there. So far, there have never been two fingerprints that have been found the same among the global population; therefore, it is inductive to believe that there are no fingerprints that are the same. Until two fingerprints are found that are indeed identical in shape and pattern then this belief cannot be falsified. Sir Karl Popper was a famous philosopher who wrote, that any theory that could not be falsified and tested to be `wrong`, could not possibly be a “scientific” experiment. The fact that Locard’s Principle explains that `every contact leaves a trace`, would surely mean that the exchange takes place between all the objects in contact. If a glass cup was placed on a wooden table, according to Locard’s principle there should be small particles of wood on the glass and glass on the wood! This exchange though is just so tiny that we today do not have the technology to prove it, therefore Locard’s Principle cannot be falsified as we can’t prove or disprove that there is an exchange.
Referring back to the method of fingerprint DNA as evidential proof of a crime, an example of this would be if Forensic
Edmond Locard (1877-1966) was a French scientist specialised in both medicine and law. Inspired by the work of Hans Gross, it was Edmond that created the concept that all objects of any material should leave traces of itself upon whatever it touches, even if it is the minutest amount, simply put as “Every Contact leaves a trace,” Locard (1923). This is commonly known as Locard’s Exchange Principle. He believed that in circumstances such as a crime, his principle could be used to find evidence of who and perhaps even how that crime was committed by finding small materials, either physical or chemical at the scene of the crime that would directly link back to the offender.
Fingerprints are a classic example of what could be left by an offender at the scene of a crime that could prove he or she was there. So far, there have never been two fingerprints that have been found the same among the global population; therefore, it is inductive to believe that there are no fingerprints that are the same. Until two fingerprints are found that are indeed identical in shape and pattern then this belief cannot be falsified. Sir Karl Popper was a famous philosopher who wrote, that any theory that could not be falsified and tested to be `wrong`, could not possibly be a “scientific” experiment. The fact that Locard’s Principle explains that `every contact leaves a trace`, would surely mean that the exchange takes place between all the objects in contact. If a glass cup was placed on a wooden table, according to Locard’s principle there should be small particles of wood on the glass and glass on the wood! This exchange though is just so tiny that we today do not have the technology to prove it, therefore Locard’s Principle cannot be falsified as we can’t prove or disprove that there is an exchange.
Referring back to the method of fingerprint DNA as evidential proof of a crime, an example of this would be if Forensic