Headaches are one effect that can come from inhalation of isopropyl alcohol. Isopropyl alcohol, or rubbing alcohol, is often used in the home or in medical facilities to treat various conditions or to sterilize instruments and skin. However, if isopropyl alcohol is inhaled there can be serious side effects.
1a) Definition of contradiction: A contradiction exists any time a proposition P is asserted to be true in conjunction with its negation, not-P. 1b) Definition of conjunction: A conjunction is a connective that joins two propositions.
Hence, there can be no largest number in the world. This was an example of a proof by contradiction, where you assume a result (such as the existence of the largest number in the world), and demonstrate that it leads to a contradiction, and is, therefore false.