There is no such thing as purely objective observation. All observation is subjective; it is always guided by the observers expectations or desires.
The speaker claims that all observation is subjective--colored by desire and expectation. While it would be tempting to concede that we all see things differently, careful scrutiny of the speakers claim reveals that it confuses observation with interpretation. In fact, in the end the speakers claim relies entirely on the further claim that there is no such thing as truth and that we cannot truly know anything. While this notion might appeal to certain existentialists and epistemologists, it runs against the grain of all scientific discovery and knowledge gained over the last 500 years.
It would be tempting to afford the speakers claim greater merit than it deserves. After all, our everyday experience as humans informs us that we often disagree about what we observe around us. Weve all uttered and heard uttered many times the phase Thats not the way I see it! Indeed, everyday observations--for example, about whether a football player was out of bounds, or about which car involved in an accident ran the red light--vary depending not only on ones spatial perspective but also on ones expectations or desires. If Im rooting for one football team, or if the player is well-known for his ability to make great plays while barely staying in bounds, my desires or expectations might influence what I think I observe. Or if I am driving one of the cars in the accident, or if one car is a souped-up sports car, then my desires or expectations will in all likelihood color my perception of the accidents events.
However, these sorts of subjective observations are actually subjective interpretations of what we observe. Visitors to an art museum might disagree about the beauty of a particular work, or even about which color predominates in that work. In a court trial several jurors might view the same videotape evidence many times, yet some jurors might observe an incident of police brutality, will others observe the appropriate use of force to restrain a dangerous individual. Thus when it comes to making judgments about what we observe and about remembering what we observe, each persons individual perspective, values, and even emotions help form these judgments and recollections. It is crucial to distinguish between interpretations such as these and observation, which is nothing more than a sensory experience. Given the same spatial perspective and sensory acuity and awareness, it seems to me that our observations would all be essentially in accord--that is, observation can be objective.
Lending credence to my position is Francis Bacons scientific method, according to which we can know only that which we observe, and thus all truth must be based on empirical observation. This profoundly important principle serves to expose and strip away all subjective interpretation of observation, thereby revealing objective scientific truths. For example, up until Bacons time the Earth was observed to lie at the center of the Universe, in accordance with the prevailing religious notion that man was the center of Gods creation. Applying Bacons scientific method Galileo exposed the biased nature of this claim. Similarly, before Einstein time and space were assumed to be linear, in accordance with our observation. Einsteins mathematical formulas suggested otherwise, and his theories have been proven empirically to be true. Thus it was our subjective interpretation of time and space that led to our misguided notions about them. Einstein, like historys other most influential scientists, simply refused to accept conventional interpretations of what we all observe.
In sum, the speaker confuses observation with interpretation and recollection. It is how we make sense of what we observe, not observation itself, that is colored by our perspective, expectations, and desires. The gifted individuals who can set aside their subjectivity and delve deeper into empirical evidence, employing Bacons scientific method, are the ones who reveal that observation not only can be objective but must be objective if we are to embrace the more fundamental notion that knowledge and truth exist.