The primary difference between logic and reason is that reason is subject to personal opinion, whereas logic is an actual science that follows clearly defined rules and tests for critical thinking. Logic also seeks tangible, visible or audible proof of a sound thought process by reasoning. Another dividing line between logic and reason is that logic is also defined as core principles and the circuit connections that carry out mathematical computations in computers, which do not and cannot reason like people can. Unlike the word "logic," "reason" is also a verb, and it refers to the action of conversing with someone in an attempt to influence or change his or her personal opinion. Therefore, a person can reason with another, but he or she cannot "logic" with another person.
Various professions and disciplines help to delineate the differences between logic and reason, which are sometimes difficult to see. For example, software developers, when coding computer programs, rely more heavily on pure logic than they do on reason, because they are essentially creating artificial intelligence in which there is no power to reason but there is the power to follow the rules of logic. Computer programmers, nevertheless, also often employ reasoning power when planning their programs to decide the most reasonable approach to achieving the goals involved. It can be said that programmers rely on logic and reason at various stages in a project. A philosopher, though, tends to rely more heavily on reason when making decisions, arriving at conclusions and determining what is rational or irrational.
Some professions require the simultaneous use of logic and reason. Healthcare providers, particularly those who work in emergency medicine, face situations in which they must use reason or make a judgment call. For example, if someone with a possible spinal cord injury is in respiratory arrest and the healthcare provider is unsuccessful in opening the airway with the jaw thrust maneuver that is used in those types of situations, he or she must quickly reason or make a judgment. If such an incident takes place when the provider is not on duty and without access to sophisticated medical equipment, he or she will determine how many attempts at the jaw thrust maneuver is a reasonable number before placing the importance of rescue breathing above the risk of aggravating a possible spinal cord injury. It would be illogical to give more importance to the spine than to getting oxygen to the brain, because of the medical proof available of the importance of the brain.
There are also times when logic and reason clash. According to the theory of aerodynamics, it is illogical to think that a bumblebee would be able to fly, but it is common knowledge that bumblebees can and do fly. What is illogical is sometimes reasonable, and what is unreasonable is sometimes logical. It is this pattern of thought along with numerous lessons seen in nature — such as the ability of a bumblebee to defy logic and fly — that help to encourage the faith of many people who see nothing illogical in a belief in the divine or other spiritual matters.