15.4 Skepticism and Justification

Skepticism challenges our ability to know anything with certainty. It questions the reliability of our senses, reasoning, and even scientific knowledge. From Descartes' evil demon to modern brain-in-a-vat scenarios, skeptical arguments push us to examine the foundations of our beliefs.

Philosophers have developed various responses to skepticism, from contextualism to fallibilism. These approaches aim to salvage knowledge claims while acknowledging our limitations. Justification theories, like foundationalism and coherentism, offer frameworks for supporting beliefs in the face of skeptical doubts.

Skepticism in Epistemology

Cartesian and Modern Skeptical Arguments

• Skepticism in epistemology challenges the possibility of certain knowledge, questioning our ability to know anything with absolute certainty
• Cartesian skeptical argument proposed by René Descartes introduces the possibility of an evil demon deceiving us about all our beliefs, including sensory experiences and logical reasoning
• Dream argument posits that we cannot distinguish between waking life and dreams, casting doubt on the reliability of our perceptions and experiences
• Brain-in-a-vat scenario, a modern version of Cartesian skepticism, proposes that we could be disembodied brains stimulated to experience a simulated reality, undermining our confidence in empirical knowledge
  • This scenario is similar to the premise of the film (The Matrix)
• Problem of the criterion, formulated by ancient skeptics, questions how we can establish criteria for knowledge without already possessing knowledge, creating a circular dilemma
  • For example, how can we determine if our senses are reliable without using our senses to verify their reliability?

Skeptical Challenges to Reasoning and Scientific Knowledge

• Regress argument challenges the justification of beliefs, arguing that any attempt to justify a belief leads to an infinite regress or circular reasoning
  • For instance, if we justify belief A with belief B, then we must justify B with C, and so on indefinitely
• Humean skepticism, based on David Hume's work, questions the validity of inductive reasoning and causal relationships, challenging the foundations of scientific knowledge
  • Hume argued that we cannot logically justify our belief in cause and effect or the uniformity of nature
  • This skepticism extends to scientific predictions based on past observations (sunrise, gravity)

Responding to Skeptical Challenges

Contextualist and Fallibilist Approaches

• Contextualism in epistemology argues that knowledge attributions are context-dependent, allowing for varying standards of knowledge in different situations
  • In everyday contexts, we might say we know the time based on our watch, while in a scientific context, more precise measurements would be required
• Fallibilism accepts that knowledge doesn't require absolute certainty, acknowledging the possibility of error while maintaining that justified true beliefs can still constitute knowledge
  • This approach allows for scientific progress despite the impossibility of absolute certainty
• Moorean shifts, inspired by G.E. Moore, attempt to reverse skeptical arguments by appealing to common sense and our strong intuitions about what we know
  • Moore famously argued "Here is one hand, and here is another" to counter skeptical doubts about the external world

Alternative Epistemological Strategies

• Externalist theories of justification, such as reliabilism, argue that knowledge can be justified by factors external to the knower's conscious awareness, potentially circumventing skeptical challenges
  • For example, our visual system might be considered a reliable process for forming true beliefs about the world, even if we're not aware of how it works
• Transcendental arguments, exemplified by Kant's approach, attempt to show that certain beliefs or knowledge are necessary preconditions for coherent experience or thought
  • Kant argued that the existence of an external world is a necessary condition for self-consciousness
• Pragmatic responses to skepticism, influenced by philosophers like William James, argue that some beliefs are justified by their practical consequences rather than their theoretical certainty
  • Believing in free will, for instance, might be justified by its positive effects on human behavior and society
• Naturalized epistemology, proposed by W.V.O. Quine, suggests replacing traditional epistemology with empirical study of how we actually form beliefs, potentially sidestepping skeptical worries
  • This approach shifts focus from abstract justification to the cognitive processes involved in belief formation

Justification for Overcoming Skepticism

Foundational Theories of Justification

• Justification in epistemology refers to the reasons or evidence that support a belief, playing a crucial role in distinguishing knowledge from mere true belief
• Foundationalism posits that some beliefs are basic or self-justifying, serving as a foundation for other justified beliefs and potentially providing a response to skeptical regress arguments
  • Basic beliefs might include simple logical truths (law of non-contradiction) or immediate sensory experiences
• Coherentism argues that justification comes from the coherence of beliefs within a system, potentially offering a holistic response to skeptical challenges
  • A scientific theory gains justification through its coherence with observed data and other established theories

Internalist and Externalist Approaches

• Internalism in justification theory holds that justifying factors must be internally accessible to the knower, raising questions about how to respond to skeptical scenarios like the brain-in-a-vat
  • An internalist might argue that we can only justify beliefs based on our conscious experiences and reasoning
• Externalism in justification theory allows for justifying factors outside the knower's awareness, potentially providing a way to maintain knowledge claims in the face of skeptical doubts
  • An externalist might argue that our beliefs can be justified by reliable cognitive processes, even if we're not aware of these processes
• Gettier problem challenges the traditional definition of knowledge as justified true belief, complicating the role of justification in overcoming skepticism
  • Gettier cases show situations where someone has a justified true belief that doesn't seem to qualify as knowledge, such as correctly guessing the time from a stopped clock
• Defeasibility theory suggests that justification can be overturned by new evidence, acknowledging the fallibilist nature of knowledge while still maintaining a role for justification in countering skepticism
  • This approach allows for the revision of beliefs in light of new information, as often occurs in scientific progress

Epistemological Theories in Practice

Scientific and Legal Applications

• Scientific knowledge claims can be analyzed using theories of justification, exploring how empirical evidence and theoretical coherence contribute to scientific understanding
  • The justification of scientific theories often involves a combination of empirical data, logical reasoning, and explanatory power
• Legal epistemology applies theories of knowledge and justification to courtroom scenarios, examining standards of evidence and the nature of testimony
  • Different legal systems employ varying standards of proof (beyond reasonable doubt, preponderance of evidence)

Social and Educational Contexts

• Social epistemology investigates how social factors influence knowledge acquisition and justification, relevant to understanding phenomena like echo chambers and fake news
  • This field examines how social media algorithms and group dynamics can shape belief formation and justification
• Theories of epistemic injustice, developed by philosophers like Miranda Fricker, explore how social prejudices can unfairly diminish one's credibility as a knower
  • Examples include dismissing someone's testimony due to their gender or race, affecting their ability to contribute to knowledge
• Virtue epistemology, which focuses on the intellectual virtues of knowers, can be applied to educational contexts to foster better critical thinking and knowledge acquisition
  • Intellectual virtues might include open-mindedness, intellectual humility, and perseverance in inquiry

Emerging Fields and Professional Knowledge

• Epistemological perspectives on artificial intelligence raise questions about machine knowledge and the nature of understanding in non-human systems
  • This includes debates about whether AI systems can truly understand or merely simulate understanding
• Theories of tacit knowledge and know-how can be applied to professional contexts, exploring how expertise is developed and justified in various fields
  • This includes understanding the nature of skills that are difficult to articulate, such as a chef's ability to season food perfectly or a doctor's intuitive diagnosis