Fallacy lives in the gray area.
So, what is a fallacy? We have things that are true, things that are false, and all the gray in between. Fallacies are the gray areas. Fallacy is not all bad. Fallacy is the basis of humor and wordplay. Fallacy is very effective in presenting the truth. Fallacy only moves over to the dark side when it’s kept in the shadows to deceive people.
A mistaken belief.
A belief is something that you accept as true without facts, through faith. If the facts prove otherwise then your belief becomes untrue, a falsehood. If the facts prove that the belief is true, then your belief takes a step up to knowing. A mistaken belief becomes a fallacy when the evidence dictates true or false and the belief is maintained.
Incorrect or invalid reasoning.
The reasoning process is very structured. It follows all the rules we learned in mathematics. Instead of numbers, we use words. If A = 1 and B = 2 and C = 3, A together with B equals C. Or 1 + 2 = 3. It is invalid and incorrect to mix it up and say C together with A equals B, or 3 + 1 = 2. What works for numbers is also valid with words. Instead of magnitudes (numbers represent the magnitudes of measurements), words represent truth values. Truth values can be combined in equations like numbers.
O, what a tangled web we weave when first we practice to deceive! Walter Scott
Making a statement that, purposely, has multiple meanings is fallacy. Presenting something as true when we know it is false is a deception. A purposeful attempt to deceive is lying. Many fallacies fall into this category.
Attributing human feelings to inanimate objects
The human mind is swayed by emotions. Applying these emotions to objects changes the perception of those objects which then sways the mind when the object is referenced. This is an insidious way to deceive and sway. It is common in advertising and politics. Propaganda uses this extensively.