Biographical Overview

Charlie Dunbar Broad was born in Harlesden, Middlesex, and educated at Dulwich College. He entered Trinity College, Cambridge, in 1905 on a natural science scholarship, studying chemistry and physics before transitioning to philosophy (then known as "moral science"). He graduated with First-Class Honours with distinction and was elected a Fellow of Trinity College in 1911. ^[1]

Broad held various prominent academic appointments throughout his life:

• Assistant Lecturer: University of St Andrews (1911–1920)

• Professor of Philosophy: University of Bristol (1920–1923)

• Knightbridge Professor of Moral Philosophy: University of Cambridge (1933–1953)

Broad led a quiet, highly structured academic life, which he famously likened in his autobiography to that of "a monk in a monastery." He deliberately avoided the intense, highly charged weekly meetings of Cambridge's Moral Science Club, which were heavily dominated by Ludwig Wittgenstein and G.E. Moore. ^[2]

The Nature of Philosophy: Critical vs. Speculative

Broad is highly regarded for how he categorized the discipline of philosophy. In Scientific Thought (1923), he divided philosophy into two distinct branches: ^[3]

Critical Philosophy

The primary task of critical philosophy is the analysis and definition of fundamental concepts (such as "cause," "change," "matter," and "mind") and the critical tracking of deeply held common-sense beliefs. Broad argued that science uses these concepts without deeply questioning them, leaving it to critical philosophy to analyze their boundaries.

Speculative Philosophy

The object of speculative philosophy is to take the results of the various sciences, combine them with human ethical and religious experiences, and reflect upon the whole to reach coherent conclusions about the nature of the universe and our position within it. Unlike many of his twentieth-century analytic contemporaries who dismissed metaphysics entirely, Broad maintained that speculative philosophy was a valid and noble pursuit.

Key Philosophical Contributions

1. Philosophy of Mind and Emergentism

In his landmark book The Mind and Its Place in Nature (1925), Broad became a foundational pioneer of emergent materialism (or emergentism). He argued that while mind and consciousness stem from physical, biological substrates, certain mental properties "emerge" at higher levels of complexity and cannot be entirely reduced to or predicted by lower-level physical laws. ^[5]

2. Philosophy of Perception and the "Sensum" Theory

Broad was a prominent defender of Representational Realism. He argued that our perception of the external world is indirect. When we look at an object (e.g., a red tomato), we are not immediately aware of the object itself. Rather, our awareness is mediated by an immediate mental entity that Broad termed a sensum (more commonly known as a sense-datum). ^[6] Even if a person experiences a total hallucination, Broad claimed that they are still directly experiencing a real "sensum."

3. Philosophy of Time: The Growing Block Theory

Broad is widely credited with one of the earliest defenses of the Growing Block Universe model of time. ^[7] In this view:

• The Past and Present are physically real.

• The Future is completely unreal; it does not exist yet.

• The present layer is the "edge" of the block, and the passage of time is the continuous growth or accumulation of new existence onto the block of reality.

4. Free Will: Agent vs. Event Causation

In his 1952 essay "Determinism, Indeterminism, and Libertarianism," Broad introduced the distinction between occurrent causation and non-occurrent causation. ^[1:1] This distinction served as the direct intellectual foundation for the modern debate between "event-causal" and "agent-causal" theories of libertarian free will. He argued that an agent, acting as a unified substance or continuant, can determine actions without those actions being fully dictated by prior events.

5. Psychical Research and Parapsychology

Unlike most analytic philosophers of his tier, Broad took a deep, dispassionate interest in parapsychology and psychical research, serving twice as the President of the Society for Psychical Research (1935 and 1958). ^[1:2] He introduced the concept of Basic Limiting Principles—the foundational, unwritten rules of nature that form the framework of modern science (e.g., that an effect cannot precede its cause). Broad defined any event that violates these basic limiting principles as "paranormal" and argued that such phenomena should be investigated scientifically rather than dismissed out of hand. ^[2:1]

Major Published Works

Broad was a prolific writer whose books were built primarily out of his meticulously prepared lecture notes:

• Perception, Physics and Reality (1914) – An exploration of what physical science can tell us about reality.

• Scientific Thought (1923) – A text focusing on the philosophy of science and the introduction of his critical/speculative philosophy framework.

• The Mind and Its Place in Nature (1925) – His magnum opus on the mind-body problem and emergentism.

• Five Types of Ethical Theory (1930) – A critical, widely read textbook analyzing the ethical systems of Spinoza, Butler, Hume, Kant, and Sidgwick.

• Examination of McTaggart's Philosophy (Vol 1: 1933, Vol 2: 1938) – A massive, exhaustive critique of his former teacher's metaphysical system.

• Religion, Philosophy and Psychical Research (1953) – A collection of essays detailing his thoughts on the paranormal and religion.

References