ABSTRACT
In this chapter, we reach back to the very beginnings of inquiry into human reason, a process that spans over 2000 years. Some of these ancient notions are still traceable in modern work. We begin with syllogistic reasoning. This was for centuries the central concern of people interested in how we think. While it may no longer be number 1, it is still an active area, with a continuous stream of ideas and results appearing. In the next chapter, we proceed to an area that can claim to have shoved syllogisms off their perch: conditional reasoning. We also look at thinking with disjunctive – Or – sentences. You will see that similar issues arise with all these apparently distinct aspects of thought.
