Mind, Matter, and Meaning

Putnam

Hilary Putnam (1926–2016) spent most of his career at Harvard and changed his mind more dramatically, more publicly, and more productively than almost any philosopher of the twentieth century. He started as a logical empiricist, became the most influential defender of functionalism, and then — in one of philosophy’s great self-reversals — published the arguments that demolished the functionalist program he had built. He championed semantic externalism, then qualified it. He eventually arrived at something close to direct realism about perception, which puts him, in his final philosophical incarnation, much closer to the book than to his own earlier positions. There is a lesson in the trajectory.

Major Works

  • “The Meaning of Meaning” (1975) — Twin Earth, semantic externalism, meanings are not in the head
  • Reason, Truth, and History (1981) — internal realism and the rejection of metaphysical realism
  • Representation and Reality (1988) — against functionalism, from the inside
  • The Threefold Cord: Mind, Body, and World (1999) — natural realism, direct perception, rejection of the interface model
  • Words and Life (1994) — collected essays including philosophy of mind and language

Key Positions

Semantic externalism and Twin Earth. Putnam’s “The Meaning of Meaning” (1975) contains the most influential thought experiment of the second half of the twentieth century in philosophy of language. Twin Earth is exactly like Earth, except that the liquid in their lakes and rivers, which they call “water,” has the chemical composition XYZ rather than H₂O. When an Earthling and their Twin Earth counterpart both think “water is wet,” they are in identical internal states. But their words mean different things: the Earthling’s “water” refers to H₂O, the Twin Earthling’s to XYZ. Meanings are not determined by what is in the head. Reference reaches out into the world, not inward into mental representations.

Multiple realization. Putnam’s original argument for functionalism: mental states can be realized in different physical substrates (carbon, silicon, who knows what). If mental states were identical to specific physical states, they couldn’t be multiply realized. Therefore mental states are functional, not physical. This argument later proved to be a double-edged sword: the same multiple realizability that supports functionalism against type identity theory also undermines functionalism against the full range of cases. A functional state realized so differently in different systems may not be the same mental state at all.

Against functionalism (the reversal). By Representation and Reality (1988), Putnam had turned against his own creation. His main objection: functionalism cannot account for the determinate content of mental states. Any sufficiently complex physical system can be interpreted as realizing any functional description; this makes functionalism trivially true and explanatorily hollow. The meaning and reference of mental states cannot be settled by functional role alone.

Natural realism and the later Putnam. The Threefold Cord (1999) is Putnam’s most important late work: a defense of “natural realism” — the view that perception puts us directly in contact with the world, not with representations or sense data that mediate between mind and world. The mind is not a box of inner representations; it is a relational, world-engaging capacity. This is not naïve realism in the sense of denying that perception can be mistaken; it is the rejection of the “interface” picture, the idea that experience always presents us with an inner screen rather than the world itself.

My View

The later Putnam is an ally, and the arc of his career is philosophically instructive in a way the book makes use of. He followed the functionalist program as far as it could go and recognized — from inside — that it couldn’t account for determinate content. He followed semantic externalism through and recognized that reference is a world-involving achievement, not a label that gets attached to inner concepts. He ended up with natural realism: the mind reaches out. That’s the book’s starting point, and it’s where Putnam’s long journey landed him.

The key contribution the book inherits is the externalism about meaning and reference. Meanings are not in the head. Reference is a world-involving, causally-historically grounded relation. “Water” means H₂O not because we have the right internal concept but because we stand in the right external relation to the stuff in our environment. This is exactly the qualified reference theory of meaning the book defends: meaning requires reference, and reference is an externalist achievement — Kripke’s causal-historical chain, Millikan’s teleosemantic grounding, Burge’s anti-individualist individuation.

The gap between Putnam’s natural realism and the book: Putnam reaches direct realism primarily by elimination — rejecting sense-datum theory and the interface model — without offering a positive account of what perception does. The book uses the Tye/Dretske identity claim to fill that gap: perception consists in the tokening of representational content of the right world-directed kind. Putnam clears the ground; the identity claim builds on it.

See Semantic Externalism, Reference, and Functionalism.

  • Semantic Externalism — Putnam’s Twin Earth argument and its legacy
  • Functionalism — Putnam’s original functionalism and his reversal
  • Reference — the book’s qualified reference theory of meaning, which Putnam’s externalism underwrites
  • Intentionality — the world-directedness Putnam’s natural realism captures