Jack Smart, who has died aged 92, changed the course of contemporary philosophy.
He was most prominent in the philosophy of mind, but also influenced many other thinkers in their approach to physical science. He was a pioneer of physicalism - the set of theories that hold that consciousness, sensation and thought do not, as they seem to, float free of physicality, but can be located in a scientific material worldview.
His article "Sensations and Brain Processes" (1959) put forward his identity theory of mind - that consciousness and sensations are nothing over and above brain processes. Invariably included in any collection of mind-body problem papers, it is now part of the canon.
Smart studied maths, physics and philosophy at Glasgow University, and during the second world war served in India and Burma. He gained a BPhil at Queen's College, Oxford, in 1948, under the behaviourist Gilbert Ryle, and in 1950 became professor at Adelaide, where he stayed until 1972.
Away from the language-centred philosophy of Britain, Smart was freer to draw the implications that science had for philosophy. He began to ask why consciousness alone should remain exempt from physico-chemical explanation.
The behaviourist view he had espoused at Oxford got round this question by denying that mental states, like anger, pain or believing, can even qualify as things or events, whether physical or non-physical. Rather, to talk about mental states is, for behaviourism, simply to talk about collections of actual or potential behaviour.
But Smart objected that in this case seeing an after-image owing to strong light can amount to nothing more than saying, "I have a yellowish-orange after-image". Such an utterance is surely superfluous to the sensation on which the utterer, who has just experienced it, would be "reporting".
Smart agreed with old-fashioned mind-body dualism - against behaviourism - that many mental states are indeed episodic, inner and potentially private; what he disputed was that this made their essential nature non-physical.
"Why should not sensations just be brain processes of a certain sort?" he asked. If regarded as neuro-physiological processes, they too would be potentially explicable by scientific laws.
In "Sensations and Brain Processes", he presented eight objections to his identity theory of brain and mind, and eight answers. One counter-argument he missed, as was pointed out, was that postulating specific neuro/mental identities restricts mental states to human brains, ignoring the brains of other species.
He was one of the leading figures to push Anglo-American analytic philosophy into collusion with the sciences. In his earliest article, "The River of Time" (1949), he invoked Einstein's special theory of relativity, arguing that our notion of time passing must be an illusion - a then-unfashionable position, which, largely thanks to him, moved more into the mainstream.
He developed "the tenseless theory of time". We should, he said, consider reality "a four-dimensional space, three of whose dimensions correspond to space in the ordinary sense of this word, and one of whose dimensions is taken to be a time dimension".
Over the years he changed his mind as to his explanation - respectively linguistic, then psychological - for why we feel as if time flows, but always remained an eternalist, claiming all points in time to be equally real. A few years ago, meeting an exponent of the opposite view, the presentist philosopher John Bigelow, at a conference, he remarked that he very much hoped that presentism is false, because, if not, this beloved friend would only be a single instantaneous time-slice: much better to regard him as an elongated and eternal space-time worm.
In "Philosophy and Scientific Realism" (1963) and subsequently, Smart acknowledged that what science tells us about the world is often hard to reconcile with how it seems in experience, but he stuck up for a reality that exists independently of our conceptions of it. He fiercely combated anti-realism, and postmodern notions that scientific theories (and the unobservable entities they depend on) are merely helpful, but arbitrary and disposable, human tools.
If successful scientific theories were not approximately true, and the entities did not more or less exist, went his "No Miracles" argument, the predictive success they have would be miraculous.
After an Episcopalian upbringing - his brother, Ninian Smart, was a theology professor - Smart had become "a reluctant atheist". Whether in philosophy of mind, philosophy of science or ethics, he strove to resolve apparently mysterious entities or values as parts of the natural world. His aim throughout was to produce a comprehensive worldview that accommodated common sense and scientific stringency.
In moral philosophy, he applied his swashbuckling approach to bringing utilitarianism - the theory that goodness consists of promoting the greatest overall happiness - back to centre stage after it had been ignored for more than 50 years.
In "An Outline of a System of Utilitarian Ethics" (1961), he embraced its then-unpopular extreme form - act utilitarianism. Its milder version, rule utilitarianism, was "superstitious rule worship", he said, and negated the deft adaptability to the actual situation that was utilitarianism's whole point.
He recognised the unpalatable upshot of his arguments - that they would sanction an innocent man being killed if greater suffering were thereby spared - but stuck to them.
In addition to his chair at the Australian National University, Canberra (1976-85), at various times Smart had visiting posts in the US at Princeton, Harvard, Yale and Stanford.
Smart was a rare phenomenon - a successful philosopher with no enemies. Brisk and down-to-earth in debate, he was never aggressive.