Deductive logic:

Deductive logic may be  considered as the opposite of  induction. Here the reasoning is more direct. If  we know a statement about a whole class of objects, phenomena or situations then we can  logically deduce the same statement about one particular object, phenomenon or situation belonging to that class. Examples of deduction are: roses can be of  any colour, hence some roses can be red. All birds have wings; therefore, a sparrow, which is a bird, will have wings. Deductive logic is extensively used in chemistry. For example, if  a group of chemical salts exhibit some properties or behaviour, we can safely say that any salt belonging to this group will exhibit the same property or behaviour. You could say that deduction may also mislead, because in the examples how do we know that a sparrow is a bird, or a salt belongs to that group of salts. These facts would have to be established before such deductions can be accepted. Thus, logical analysis takes us from the known to the unknown and it involves an element of isk or doubt. Hence, the hypotheses arrived at from both kinds of reasoning have to be tested before they are accepted. A major operation  in the method of science  is that of setting up experiments specifically designed to test the hypotheses.