Though fuzzy logic is still quite a young field, many of its ideas originated in the time of the ancient Greeks. The "Laws of Thought" were posited. One of these, the "Law of the Excluded Middle," states that every proposition must either be True or False. Even when Parminedes proposed the first version of this law (around 400 B.C.) there were strong and immediate objections. For example, Heraclitus proposed that things could be simultaneously true and not true. Plato probably made one of the most important contributions to fuzzy logic by demonstrating that there is a third region beyond true and false. In the 1900's Lukasiewicz was the first to propose a systematic alternative to the bi-valued logic, which Aristotle had formulated. Lukasiewicz had created a tri-valued logic, where there is a true (2), a false (0) and a possible (1) response. He then experimented with a four-valued logic and declared that it is possible to create an infinite-valued logic. The advantage of this was not realized until 1965 when Lotfi A. Zadeh publish the paper "Fuzzy Sets" which describe the mathematics of fuzzy set theory and in turn also described fuzzy logic (which is mentioned above). Zadeh also formulated the concept of fuzzy control that allows a small set of intuitive rules to be used in order to control the operation of electronic devices such as home appliances. Fuzzy control allows the appliance to adapt automatically to different conditions. For instance, a vacuum cleaner would apply more suction to an especially dirty area. Another prominent feature of the fuzzy system is its ability to define hedges.