[15] See Vailati, _Journal of Philosophy, Psychology, and Scientific Methods_, Vol. V, No. 12. [Sidenote: Scientific induction and deduction] This more systematic thinking is, however, like the cruder forms in its double movement, the movement _toward_ the suggestion or hypothesis and the movement _back_ to facts. The difference is in the greater conscious care with which each phase of the process is performed. _The conditions under which suggestions are allowed to spring up and develop are regulated._ Hasty acceptance of any idea that is plausible, that seems to solve the difficulty, is changed into a conditional acceptance pending further inquiry. The idea is accepted as a _working hypothesis_, as something to guide investigation and bring to light new facts, not as a final conclusion. When pains are taken to make each aspect of the movement as accurate as possible, the movement toward building up the idea is known as _inductive discovery_ (_induction_, for short); the movement toward developing, applying, and testing, as _deductive proof_ (_deduction_, for short). [Sidenote: Particular and universal] While induction moves from fragmentary details (or particulars) to a connected view of a situation (universal), deduction begins with the latter and works back again to particulars, connecting them and binding them together. The inductive movement is toward _discovery_ of a binding principle; the deductive toward its _testing_--confirming, refuting, modifying it on the basis of its capacity to interpret isolated details into a unified experience. So far as we conduct each of these processes in the light of the other, we get valid discovery or verified critical thinking. [Sidenote: Illustration from everyday experience] A commonplace illustration may enforce the points of this formula. A man who has left his rooms in order finds them upon his return in a state of confusion, articles being scattered at random. Automatically, the notion comes to his mind that burglary would account for the disorder. He has not seen the burglars; their presence is not a fact of observation, but is a thought, an idea. Moreover, the man has no special burglars in mind; it is the _relation_, the meaning of burglary--something general--that comes to mind. The state of his room is perceived and is particular, definite,--exactly as it is; burglars are inferred, and have a general status. The state of the room is a _fact_, certain and speaking for itself; the presence of burglars is a possible _meaning_ which may explain the facts. [Sidenote: of induction,] So far there is an inductive tendency, suggested by particular and present facts. In the same inductive way, it occurs to him that his children are mischievous, and that they may have thrown the things about. This rival hypothesis (or conditional principle of explanation) prevents him from dogmatically accepting the first suggestion. Judgment is held in suspense and a positive conclusion postponed.