Deciding what is probably case based on one"s knowledge. Involves inductive leap since no guarantee of correctness. Involves making hypothesis, then test to see result supports or falsifies. Hypothesis never proven so falsification should be priority. Confirmation bias: people tend to test hypotheses by seeking confirming evidence than attempting falsification. Observed for both ordinary people and professional scientists. Viewed laws of logic as laws of thoughts, not true. People capable of reasoning logically, but sometimes fail to do so. Can improve by being aware of biases and seeking disconfirming. Making decisions hard because alternatives have many dimensions and seldom does best alternative excel on all. Additive model: combine good and bad dimensions for total score. Weighted-additive model: weigh some dimensions more than others. Additive-difference model: compare alts dimension by dimension to focus on key differences. Dimension so unattractive that results in elimination. Elimination by aspects: sequential evaluation, if dimension doesn"t satisfy min, jail.