Deductive logic is a powerful thing. We have a body of knowledge, and a body of theory about how that knowledge makes sense together. From that, we create hypotheses to move that theory into some marginally new area, to see if the theory explains what we're about to see during the experiment.
Le Corbusier wrote “A house is a machine that you live in. To build such a machine, you need the sun, the sky, the trees, steel and cement — strictly in that hierarchical order. If only with these materials you build, ingenuity is at work and suddenly you touch my heart, you do me good. I am happy and I say this is beautiful.” But Corbu was famous for not caring what people thought of living with his designs, for wanting to educate people into appreciating what he appreciated. He worked out his hypotheses by attending to the first half of his maxim -- the tightly limited palette, the intellectual hierarchy -- but neglected the part about touching our hearts.
Every profession has the tendency to focus on the work that it understands and the outcomes it can directly impact. Your doctor probably focuses more on your blood pressure than s/he does on your enjoyment of life, because s/he understands the physiology of blood pressure and the pharmacological possibilities of its treatment. And yet you, the inhabitor of the body the doctor examines, probably have no idea what your blood pressure is at any particular moment; you know that you feel good, or tired, or lightheaded. For you, blood pressure is not the end goal -- feeling good is the end goal.
So too for buildings. Designers are interested in buildings, but most of us aren't. We're interested in having our work be productive, our family be happy, our neighborhoods be safe and sociable. If our buildings can help those things be true, then they're fine; if not, they just don't work. The building is not the outcome. The outcome is the outcome.
So I'm interested in looking for examples of happy, productive, lively, intelligent people, and then trying to figure out if there are any commonalities to the places in which they have those experiences. I want to build theory inductively, trying to assemble a body of good experiences and understanding what ties those experiences together. If we HAD a workable theory of design's impact on those satisfactions, then we could be deductive, but we still live in a world that's prior to that point (and may always be short of that goal). We have to quit thinking so much about form and space and material, and far more about joy.