Philosophy Monday: The Role of Instruments in Science

The use of instruments and tools to understand, measure, and record the natural world may be a staple of modern scientific inquiry, but the relationship between the instruments and their validity in describing the natural world has developed over time. This relationship has changed considerably since the earliest recorders of Greek natural philosophy started over 2000 years ago. In order to organize this mutual development of the tools and our understanding of the natural world, I consider three periods of developments: the passive instrument, the active instrument, and the transcendent instrument. Each of these periods required new philosophical underpinnings before the scientific tools could be accepted and used.

In the first period, the passive instrument phase, the use of scientific instruments can best be seen in Aristotle’s work. He accepted observations based on personal experience and perception. Aristotle saw direct experimentation as a manipulation of the natural world and antithetical to an understanding of the natural world. He would have rejected outright the use of most scientific instrumentation since it distorts and alters the natural state of things. Only the information available to sense perception can be reflective of the real world.

The passive nature of the instruments does not alter perception at all, only assist it. In The Elements by Euclid, the only permitted instruments were a straight edge and compass which merely corrected for the imperfection in the mind-body connection (e.g. we are poor circle-drawers). This trend is seen throughout the science of this period in the lack of quantitative measurements – barring ruler-like use such as in measuring star location. Par exemplar, Tycho Brahe relied on simple tools designed to be accessories to his perception. The azimuthal quadrant and sextant functioned only as accurately as Brahe was accurate since it did not provide more information than what was available to the naked eye (Brahe 401). These tools only permitted measurements of what could be seen. This was true of all the instruments designed and operated by astronomers and other scientists until Galileo developed the telescope.

The second period is focused largely on the astronomical discipline and transitions during the interim of Tycho Brahe and Galileo. Tycho Brahe and his predecessors were firmly still in the first period of instrument usage whereas Galileo introduced the next generation of astronomers to a new class of instrument.

Galileo developed the telescope in the year 1609 and turned it to making astronomical observations in the 1610s (McMullien). While this achievement was revolutionary, many people of today would be incredulous to hear some of the negativity towards the telescope when first introduced to astronomers. The telescope did not instantly revolutionize the astronomic field upon its introduction, instead it took many years for professional astronomers to accept the use of this sort of instrument. And while it can be argued that the slow uptake was due to a number of factors, I argue that the shift from human-limited perception to an instrument-limited perception was a difficult transition. This was the first time when measurements were no longer restricted to the information available by our senses; instead, these new scientific instruments could provide the astronomer and scientist information beyond the Idol of the Tribe. These passive tools could permit a hundred fold improvement in measurements and observations over the unaided individual. This change raised questions of the nature of reality and what can be considered real, since afterwards the world appeared orders of magnitudes more complex than it had previously seemed. The new accuracy gained with these active instruments not only disproved the old theories but often times restated the questions such as entirely new approaches were required. This is what happened in the story of Newton’s Universal Law of Gravitation since the then classical physics failed to be malleable to the new observations. These refinements necessitate Kuhn’s paradigm shifts because updates to the old theories no longer provide a suitable option.

The final phase in scientific instruments took place when chemistry came of age in the late 1700s. The hurdles faced in the development of atomic and molecular theories generated a great incentive to produce new instrumentation to measure and test for upstanding in the largely ‘dark room’ of chemistry[1]. Lavoisier produced an ingenious new device which measures the heat produced or given off by an object of interest. This calorimeter exemplifies the final stage of scientific instrumentation since it no longer measured or recorded a quantity which is accessible to human senses. While the sense of touch is nearly limited to a binary measurement of ‘hot’ or ‘cold’, Lavoisier’s new tool could actually measure heat and energy. This, along with a plethora of other novel instruments, provides access to information otherwise inaccessible to human senses. This final phase of transcendent instruments has, in my estimation, destroyed any hope for human omniscience.

Our sense of a rational universe has had to adapt to these new sources of information and experiences beyond our own perceptions. Throughout our recorded history, philosophers have posed this single, fundamental question regarding the natural world: how could information unknowable to the senses ever truly be taken as real. Just as the amount of information available to scientists multiplied to unfathomable levels with the transition to the period of active instruments, so too did it again with transcendent instruments[2]. Now scientists are researching phenomenon and measuring effects unperceivable and which border on the unfathomable, such is the case with particle physics.


  1. Science as the fumbling search in a dark room for a black cat.
  2. For more on the topic of information overload I highly recommend checking out The Information: a history, a theory, a flood by James Gleick.