Understanding What It Means When Scientists Say Something Exists
In many public lectures and casual conversations, a recurring question arises: Do certain entities—like black holes, quarks, or gravitational waves—really exist? Often, skeptics challenge scientists by implying that these phenomena are analogous to beliefs or illusions rather than concrete realities. But what does it really mean when scientists say that something exists?
The Distinction Between Belief and Scientific Knowledge
The speaker begins by emphasizing a crucial point: Scientists do not deal in beliefs but in data and hypotheses. Unlike personal beliefs or philosophical assertions, science is rooted in empirical evidence, mathematical models, and reproducible predictions.
When a scientist says, "We have observed gravitational waves", they are referring to the fact that the mathematical framework of Einstein's general relativity predicted certain phenomena, and these predictions have been verified through experiments—namely, observations made by the LIGO and VIRGO gravitational wave detectors.
Mathematical Structures and Predictions
Key to understanding scientific claims is recognizing that many concepts—such as black holes, gravitational waves, quarks, or the Higgs boson—are mathematical structures. These are parts of a theoretical framework that can be used to derive specific, testable predictions.
Gravitational waves are ripples in spacetime predicted by Einstein's equations. When experiments detect these waves, it is the predictions derived from the equations that are being confirmed, not necessarily the "thing in the sky" called a gravitational wave in an absolute sense.
Similarly, quarks and the Higgs boson are elements of the Standard Model of particle physics. Their "existence" is confirmed when the model's predictions match experimental observations, such as particles appearing in detectors at the right energy levels.
This approach is analogous to forecast models in weather prediction: the models are mathematical, and their success hinges on whether the predictions align with what is observed.
The speaker raises an important philosophical point: "What does it mean for something to be 'real' or 'true'?"
This isn’t always straightforward, and the answer often depends on philosophical stance. Many scientists subscribe to a philosophy called "realism", which suggests that the elements of a successful scientific theory have an extra property: they are really there, beyond just being useful tools.
However, realism is a philosophical choice, not a scientific fact. Science itself doesn't prescribe whether these entities are "truly real". Instead, it provides a framework in which predictions and observations align.
If someone claims, "The Higgs boson does not exist," the responsibility is on them to show that the theory, predictions, or observations are incompatible. It’s not enough to simply deny the entity's existence; they must demonstrate that the mathematical structure fails to match experimental data.
Similarly, with entities like black holes, claiming they don't exist would mean showing that the observations attributed to black holes can be explained without them—something that current evidence does not support.
The Final Word: Scientific Claims are About Evidence, Not Belief
The bottom line is simple yet profound: In science, an assertion of existence is about the agreement between mathematical models and observed data. When the data matches the predictions derived from a theory, scientists say that the structures modeled—be they gravitational waves, quarks, or time—“exist” in the sense that they are consistent with reality as revealed through measurements.
The speaker humorously concludes with a playful challenge: “Do you think I exist?” This reminds us that questions about existence often have philosophical underpinnings, but in the realm of empirical science, what matters is the evidence and the predictive power of our theories.
In summary, scientific "existence" hinges on consistent, reproducible evidence that confirms the predictions of our models. While philosophy debates what it truly means for something to be real or true, science pragmatically relies on empirical data, mathematical frameworks, and the predictive accuracy that these frameworks afford.
Part 1/7:
Understanding What It Means When Scientists Say Something Exists
In many public lectures and casual conversations, a recurring question arises: Do certain entities—like black holes, quarks, or gravitational waves—really exist? Often, skeptics challenge scientists by implying that these phenomena are analogous to beliefs or illusions rather than concrete realities. But what does it really mean when scientists say that something exists?
The Distinction Between Belief and Scientific Knowledge
The speaker begins by emphasizing a crucial point: Scientists do not deal in beliefs but in data and hypotheses. Unlike personal beliefs or philosophical assertions, science is rooted in empirical evidence, mathematical models, and reproducible predictions.
Part 2/7:
When a scientist says, "We have observed gravitational waves", they are referring to the fact that the mathematical framework of Einstein's general relativity predicted certain phenomena, and these predictions have been verified through experiments—namely, observations made by the LIGO and VIRGO gravitational wave detectors.
Mathematical Structures and Predictions
Key to understanding scientific claims is recognizing that many concepts—such as black holes, gravitational waves, quarks, or the Higgs boson—are mathematical structures. These are parts of a theoretical framework that can be used to derive specific, testable predictions.
For instance:
Part 3/7:
Gravitational waves are ripples in spacetime predicted by Einstein's equations. When experiments detect these waves, it is the predictions derived from the equations that are being confirmed, not necessarily the "thing in the sky" called a gravitational wave in an absolute sense.
Similarly, quarks and the Higgs boson are elements of the Standard Model of particle physics. Their "existence" is confirmed when the model's predictions match experimental observations, such as particles appearing in detectors at the right energy levels.
This approach is analogous to forecast models in weather prediction: the models are mathematical, and their success hinges on whether the predictions align with what is observed.
The Role of Philosophy in Scientific Existence
Part 4/7:
The speaker raises an important philosophical point: "What does it mean for something to be 'real' or 'true'?"
This isn’t always straightforward, and the answer often depends on philosophical stance. Many scientists subscribe to a philosophy called "realism", which suggests that the elements of a successful scientific theory have an extra property: they are really there, beyond just being useful tools.
However, realism is a philosophical choice, not a scientific fact. Science itself doesn't prescribe whether these entities are "truly real". Instead, it provides a framework in which predictions and observations align.
Challenging the Notion of Existence
Part 5/7:
If someone claims, "The Higgs boson does not exist," the responsibility is on them to show that the theory, predictions, or observations are incompatible. It’s not enough to simply deny the entity's existence; they must demonstrate that the mathematical structure fails to match experimental data.
Similarly, with entities like black holes, claiming they don't exist would mean showing that the observations attributed to black holes can be explained without them—something that current evidence does not support.
The Final Word: Scientific Claims are About Evidence, Not Belief
Part 6/7:
The bottom line is simple yet profound: In science, an assertion of existence is about the agreement between mathematical models and observed data. When the data matches the predictions derived from a theory, scientists say that the structures modeled—be they gravitational waves, quarks, or time—“exist” in the sense that they are consistent with reality as revealed through measurements.
The speaker humorously concludes with a playful challenge: “Do you think I exist?” This reminds us that questions about existence often have philosophical underpinnings, but in the realm of empirical science, what matters is the evidence and the predictive power of our theories.
Part 7/7:
In summary, scientific "existence" hinges on consistent, reproducible evidence that confirms the predictions of our models. While philosophy debates what it truly means for something to be real or true, science pragmatically relies on empirical data, mathematical frameworks, and the predictive accuracy that these frameworks afford.