Deductive and Inductive Reasoning

Inductive Reasoning involves an observer to look at the evidence around them and draw a conclusion about said evidence. Inductive statements are probable statements that can be highly likely or have a low probability of being correct. In a good inductive argument, the premises probabilize the conclusion. That is, if the premises are all true, then the conclusion probably is true. Inductive statements in forensics is usually referred to as circumstantial evidence. Example: At the crime scene there were footprints of tennis shoes, size 9, the defendant wears size 9 shoes, this could possibly place the defendant at the scene of the crime.

Usually leads to more than one possibility. Starts with observations where assumptions are made. Usually deal with probabilities. Example: I dropped a ball and it fell. If I dropped the ball again it will fall. Assumption: Because it happened already, I can predict it will happen again.

Deductive Reasoning involves an established law or theory when looking at evidence, where usually only one conclusion can be made. In a good deductive argument, the premises entail the conclusion. That is, if the premises are all true, then the conclusion has to be true. Deductive Statements in Forensics are usually referred to as concrete or solid evidence. Example: Transference occurs at every crime scene. There are bloody footprints leading away from the crime scene. If we find the person that owns the bloody shoes that match the blood at the crime scene, then we can place that person at the scene of the crime.

Usually leads to more one conclusion. Starts with theory or scientific principle/fact. Example: The law of gravity states that if I drop a ball it will fall. I dropped the ball and it fell. Conclusion: Based on the theory of gravity, I could deduce that the ball would fall if I dropped it.