Statement 2: As part of their life cycle, trees take carbon dioxide from the air and use it to make cellulose and other molecules. Therefore, trees reduce carbon dioxide levels in the air.

Comments: This one is complicated because we can’t see the carbon dioxide with our natural human senses. Besides, trees do not use carbon dioxide alone to make their structures. In order to have an understanding of the process of turning carbon dioxide into cellulose, we would need to have a fairly strong background in biology and chemistry. Do deciduous trees make cellulose in the winter? The old saying, “Socrates is a man and all men are mortal, so Socrates is mortal” is an artificial example that is not terribly helpful in sorting out the actual problems humans encounter.

Finding: There are two classical types of logic: deductive and inductive. If you think hard about how we come to embrace the truth of logical statements, they all started with observations of features in the world that the observers used to reach conclusions. This is deductive logic. Nobody can ever be justifiably sure that they made enough observations to reach a firm, eternal, valid conclusion.

Inductive logic, on the other hand, starts with a theory that someone came up with by using the previously described deductive logic. The best use of logic in everyday technical work is usually using data to create a theory and then looking to see if the theory matches, or is consistent with, other known and accepted theories. If it does, that is one aspect of building justifiable confidence.

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