While modern science seems committed to the idea that seeking verifiable facts that are accessible to anyone is a good strategy for building a reliable picture of the world as it really is, historically, these two ideas have not always gone together. Peter Machamer describes a historical moment when these two senses of objectivity were coupled in his article, “The Concept of the Individual and the Idea(l) of Method in Seventeenth-Century Natural Philosophy.” 
Prior to the emergence of a scientific method that stressed objectivity, Machamer says, most people thought knowledge came from divine inspiration (whether written in holy books or transmitted by religious authorities) or from ancient sources that were only shared with initiates (think alchemy, stone masonry, and healing arts here). Knowledge, in other words, was a scarce resource that not everyone could get his or her hands (or brains) on. To the extent that a person found the world intelligible at all, it was probably based on the story that someone else in a special position of authority was telling.
How did this change? Machamer argues that it changed when people started to think of themselves as individuals. The erosion of feudalism, the reformation and counter-reformation, European voyages to the New World (which included encounters with plants, animals, and people previously unknown in the Old World), and the shift from a geocentric to a heliocentric view of the cosmos all contributed to this shift by calling old knowledge and old sources of authority into question. As the old sources of knowledge became less credible (or at least less monopolistic), the individual came to be seen as a new source of knowledge.
Machamer describes two key aspects of individuality at work. One is what he calls the “Epistemic I.” This is the recognition that an individual can gain knowledge and ideas directly from his or her own interactions with the world, and that these interactions depend on senses and powers of reason that all humans have (or could have, given the opportunity to develop them). This recognition casts knowledge (and the ability to get it) as universal and democratic. The power to build knowledge is not concentrated in the hands (or eyes) of just the elite -- this power is our birthright as human beings.
The other side of individuality here is what Machamer calls the “Entrepreneurial I.” This is the belief that an individual's insights deserve credit and recognition, perhaps even payment. This recognition casts the individual who has it as a leader, or a teacher -- definitely, as a special human worth listening to.
Pause for a moment to notice that this tension is still present in science. For all the commitment to science as an enterprise that builds knowledge from observations of the world that others must be able to make (which is the whole point of reproducibility), scientists also compete for prestige and career capital based on which individual was the first to observe (and report observing) a particular detail that anyone could see. Seeing something new is not effortless (as we've discussed in the last two posts), but there's still an uneasy coexistence between the idea of scientific knowledge-building as within the powers of normal human beings and the idea of scientific knowledge-building as the activity of special human beings with uniquely powerful insights and empirical capacities.
The two “I”s that Machamer describes came together as thinkers in the 1600s tried to work out a reliable method by which individuals could replace discredited sources of "knowledge" and expand on what remained to produce their own knowledge. Lots of "natural philosophers" (what we would call scientists today) set out to formulate just such a method. The paradox here is that each thinker was selling (often literally) a way of knowing that was supposed to work for everyone, while simultaneously presenting himself as the only one clever enough to have found it.
Looking for a method that anyone could use to get the facts about the world, the thinkers Machamer describes recognized that they needed to formulate a clear set of procedures that was broadly applicable to the different kinds of phenomena in the world about which people wanted to build knowledge, that was teachable (rather than being a method that only the person who came up with it could use), and that was able to bring about consensus and halt controversy. However, in the 1600s there were many candidates for this method on offer, which meant that there was a good bit of controversy about the question of which method was the method.
Among the contenders for the method, the Baconian method involved cataloguing many experiences of phenomena, then figuring out how to classify them. The Galilean method involved representing the phenomena in terms of mechanical models (and even going so far as to build the corresponding machine). The Hobbesian model focused on analyzing compositions and divisions of substances in order to distinguish causes from effects. And these were just three contenders in a crowded field. If there was a common thread in these many methods, it was describing or representing the phenomena of interest in spatial terms. In the seventeenth century, as now, seeing is believing.
In a historical moment when people were considering the accessibility and the power of knowledge through experience, it became clear to the natural philosophers trying to develop an appropriate method that such knowledge also required control. To get knowledge, it was not enough to have just any experience -– you had to have the right kind of experiences. This meant that the methods under development had to give guidance on how to track empirical data and then analyze it. As well, these methods had to invent the concept of a controlled experiment.
Whether it was in a published dialogue or an experiment conducted in a public space before witnesses, the natural philosophers developing knowledge-building methods recognized the importance of demonstration. Machamer writes:
Demonstration … consists in laying a phenomenon before oneself and others. This "laying out" exhibits the structure of the phenomenon, exhibits its true nature. What is laid out provides an experience for those seeing it. It carries informational certainty that causes assent.” (94)
Interestingly, there seems to have been an assumption that once people hit on the appropriate procedure for gathering empirical facts about the phenomena, these facts would be sufficient to produce agreement among those who observed them. The ideal method was supposed to head off controversy. Disagreements were either a sign that you were using the wrong method, or that you were using the right method incorrectly. As Machamer describes it:
[T]he doctrines of method all held that disputes or controversies are due to ignorance. Controversies are stupid and accomplish nothing. Only those who cannot reason properly will find it necessary to dispute. Obviously, as noted, the ideal of universality and consensus contrasts starkly with the increasing number of disputes that engage these scientific entrepreneurs, and with the entrepreneurial claims of each that he alone has found the true method.
Ultimately, what stemmed the proliferations of competing methods was a professionalization of science, in which the practitioners essentially agreed to be guided by a shared method. The hope was that the method the scientific profession agreed upon would be the one that allowed scientists to harness human senses and intellect to best discover what the world is really like. Within this context, scientists might still disagree about the details of the method, but they took it that such agreements ought to be resolved in such a way that the resulting methodology better approximated this ideal method.
The adoption of shared methodology and the efforts to minimize controversy are echoed in Bruce Bower’s  discussion of how the ideal of objectivity has been manifested in scientific practices. He writes:
Researchers began to standardize their instruments, clarify basic concepts, and write in an impersonal style so that their peers in other countries and even in future centuries could understand them. Enlightenment-influenced scholars thus came to regard facts no longer as malleable observations but as unbreakable nuggets of reality. Imagination represented a dangerous, wild force that substituted personal fantasies for a sober, objective grasp of nature. (361)
What the seventeenth century natural philosophers Machamer describes were striving for is clearly recognizable to us as objectivity -– both in the form of an objective method for producing knowledge and in the form of a body of knowledge that gives a reliable picture of how the world really is. The objective scientific method they sought was supposed to produce knowledge we could all agree upon and to head off controversy.
As you might imagine, the project of building reliable knowledge about the world has pushed scientists in the direction of also building experimental and observational techniques that are more standardized and require less individual judgment across observers. But an interesting side-effect of this focus on objective knowledge as a goal of science is the extent to which scientific reports can make it look like no human observers were involved in making the knowledge being reported. The passive voice of scientific papers -- these procedures were performed, these results were observed -- does more than just suggest that the particular individuals that performed the procedures and observed the results are interchangeable with other individuals (who, scientists trust, would, upon performing the same procedures, see the same results for themselves). The passive voice can actually erase the human labor involved in making knowledge about the world.
 "The Concept of the Individual and the Idea(l) of Method in Seventeenth-Century Natural Philosophy," in Peter Machamer, Marcello Pera, and Aristides Baltas (eds.), Scientific Controversies: Philosophical and Historical Perspectives. Oxford University Press, 2000.
 Bruce Bower, “Objective Visions,” Science News. 5 December 1998: Vol. 154, pp. 360-362