•Reasoning by analogy is a very powerful
concept.
•Given two objects are similar in some way, it
is probable that they will
be similar in some other related way.
•In chemistry, this sort of reasoning allowed
Mendeleev to construct the periodic table, without a knowledge of atomic
structure.
•“I began to look about and write down the elements
with their atomic
weights and typical properties, analogous elements and like
atomic weights on separate cards, and this soon convinced me that the properties of elements are in periodic
dependence upon their
atomic weights.”
--Mendeleev, Principles of Chemistry, 1905, Vol. II