These "sensationalist" ideas that were developed in the 17th cent. are very nice ideas. At the stage when you have no "science" yet, the first thing that "works" will do; it will be very nice. It's great. You have a square peg that fits into a square hole; and this feels nice to you.
It needs to work. It can't be just anything. It must work for you; it just has to sound good, or good enough. That itself is the requirement—a "nice" feeling. Later, you can start arguing over competing paradigms—which is to say between a plurality of more than one of the "paradigms," to use Thomas Kuhn's term. But my how slowly this Western civil society moves forward like an inchworm. It seems that way to me, and Sachs says that the influence of Newton and Locke has continued to be in force in some sense. Sacks seems to say that all the way up until the seventies it was hard for alternative views to get a fair hearing. Imagine that. OK, the seventies are not yesterday, but, pretty close to it. Well, at least that's the way I read Sachs—he actually said the seventies I think.
So, you finally get to the next stage where the first thing isn't the obviousity that it was, and now you at least have a choice of two contrasting theories. Congrats, Western Civ!!! Now they can battle it out. But at the earlier stage, when the thinking fellers' club has but one, the "sensationalist" theory seems fine, nice even, not to mention, Well—sensational. Because there is no competition. This also causes the famous dictum, "I think therefore I am," to morph into, "It wins because it is."
The Lockean or the Newtonian theory will do. That's the one—that'll do. It wins because it is. At that point, it's wiggling on stage like a lone burlesque dancer in a crowded theatre. There was no other idea of how the thing might work. Specfically, then what are they all a-fire about? What's the Lockean theory of sensation?
The theory seems to theorize that the sense-data itself is merely a (Sachs says "passive") transmission of what "really" "is." This is commuted piece by piece from the object to the subject, or to the person doing the receiving of data. It sounds to me like the data has existence. And it is perceived by the eye, and this data, or "sense-data," is projected onto a film screen on the back of the head where the "self," whoever that is, somehow "reads" the information. Do I do the idea justice?
And today there is a big argument about whether this is the right idea or not. Or, at any rate, according to Sachs, the sensationalist (or physicalist) theory (of Locke or Newton) held up (or should I say constituted?)scientific progress from the mid-17th cent to the late 19th. OMG. And as long as the philosophers, who have now been replaced by a priestly class called "scientist," hold to the older way of putting the world together they will be doctrinal—which is to say that they will hold to their doctrine and reject any information that contradicts their primary doctrinal bias. "Doctrinal" is, again, Sachs' word, in his book.
I would also like to add that—maybe—the Lockean theory that Sachs describes may have not been that bad. That would mean that "science" has a little more to do with "fiction" than we might suppose it does. Maybe the word we associate with "science" should not be "truth" but something else, like "theory." At the beginning, according to this two-part series of essays, anything that "works for you" is acceptable, since you have no explanation. You have zero explain. "Science" ain't been invented yet; nor do you have "philosophy or science" or "history of ideas." You just have people, and ideas. At that stage you are still trying to invent science. Science is innovation and creativity and excitement; only the greats know that.