Searle on Mind and Brain

Searle on Mind and Brain

Searle maintained that the mind is a higher-level property of the brain, not a separate substance. There is only the physical world with higher- and lower-level descriptions. This is his solution to the mind-body problem. He liked to compare the mental to the liquid: there is only a world of H2O molecules (lower-level) with liquidity (higher-level) tacked on. The liquidity follows from the molecular composition; it isn’t another thing. Thinking is to neurons what liquidity is to molecules. Problem solved. But is it? It is a good (and familiar) thought that the mind is an aspect of the brain not another separate entity, but is the relation between brain and mind like the relation between H2O molecules and liquid water? Searle would say we can’t find liquidity in individual molecules—they aren’t liquid—but in the aggregate liquidity is the natural outcome (the molecules slide around each other). Liquidity is an aggregate property (“holistic”) not a component property (“individualistic”). Similarly, consciousness is an aggregate holistic property of individual neurons. There is no mystery here, just the logic of wholes and parts, collections and their members. But the problem with this idea is glaring: consciousness isn’t an aggregate property—it is both more and less than that. Neurons aggregate into ganglia and brain regions (e.g., the hypothalamus), but these aggregates are not states of mind, just more complex chunks of brain tissue. The neurons are not elements in a cerebral soup (the brain isn’t liquid) but parts of a relatively solid object. The solidity of the brain is not the mind. But what other relations between neurons could add up to the mind? Nothing we can discern. The neurons are precisely unlike H2O molecules; their composition does not produce mentality according to basic physics and chemistry. Nor does it seem possible for neurons to aggregate into minds. If we liquify the brain, we don’t produce the mind! So, the analogy is exactly wrong: the mind is nothing like liquidity (or solidity or gaseousness or a wrinkled shape or a chestnut). It rather illustrates the nature of the real mind-body problem: we have no account of how the brain produces the mind—no account at all. It isn’t a matter of mere detail; we have no idea how the brain can have a mental aspect. The only aggregative properties we know of don’t produce it. And it looks as if no amount of aggregating and interrelating will ever lead from neurons to thoughts and sensations. The mind is not a feature of collections qua collections. It is not a macro feature of collections of micro entities. Searle’s favorite analogy thus disproves his own theory; it shows up the glaring lacuna at its heart. All the hard work has to be done at the level of relating (collections of) neurons to mental phenomena; that is the problem. And the threat of dualism still looms over us: maybe the brain doesn’t and can’t produce consciousness from its own limited neural resources. Neurons are like molecules that won’t slide over each other. No amount of insistence that consciousness is a biological phenomenon (true as that is) will overcome this problem. Searle’s theory is at best a place-holder for a theory not a theory.