In the sense that Aristotle used empirical methods rather
than concentrate on mathematics as did Plato, I consider him an empiricist. In
this sense, the post Aristotelians that were also empiricists would be the Epicureans, the Stoics,
the Skeptics and perhaps the Cynics. The name Sextus Empiricus,
who was the philosopher that is our chief source of information on ancient
skepticism, literally means the “sixth sense.”
Hume is considered the skeptic par excellence and is one of the British empiricists that started with Bacon.
There are contemporary skeptics.
Stanford’s IEP entry on “Empiricism”
Kant says: “And thus universal empiricism reveals itself as absolute skepticism. Empiricism, on the contrary, cuts up at the roots the morality of intentions (in which, and not in actions only, consists the high worth that men can and ought to give to themselves), and substitutes for duty something quite different, namely, an empirical interest, with which the inclinations generally are secretly leagued; and empiricism, moreover, being on this account allied with all the inclinations which (no matter what fashion they put on) degrade humanity when they are raised to the dignity of a supreme practical principle; and as these, nevertheless, are so favourable to everyone's feelings, it is for that reason much more dangerous than mysticism, which can never constitute a lasting condition of any great number of persons.”
William James certainly shows pragmatists should be considered empiricists in his Will to Believe. From James “Will to Believe” 5.
“Empiricism and Absolutism. It will be observed that for the
purposes of this discussion we are on 'dogmatic ' ground, -- ground, I mean,
which leaves systematic philosophical skepticism altogether out of account. The
postulate that there is truth, and that it is the destiny of our minds to
attain it, we are deliberately resolving to make, though the skeptic will not
make it. We part company with him, therefore, absolutely, at this point. But
the faith that truth exists, and that our minds can find it, may be held in two
ways. We may talk of the empiricist way and of the absolutist way
of believing in truth. The absolutists in this matter say that we not only can
attain to knowing truth, but we can know when we have attained to
knowing it; while the empiricists think that although we may attain it, we
cannot infallibly know when. To know is one thing, and to know for
certain that we know is another. One may hold to the first being
possible without the second; hence the empiricists and the absolutists,
although neither of them is a skeptic in the usual philosophic sense of the
term, show very different degrees of dogmatism in their lives.”
In this section we have at once an analysis of empiricism and a Criticism of the Kantian solution of the problem of empiricism. It is shown that if phenomena are appearances of noumena, then the noumena do appear, and are, in fact, nothing except so far as they appear: otherwise the noumena, so far being "hidden", are worse than appearances, they are illusion. The phenomena are not merely appearances "to the mind", but appearances of something that does make itself manifest. If phenomena are thus not external to and still less independent of noumena, noumena are just as truly immanent in phenomena. Treated in any other way, noumena can at best be only another kind of phenomena; and this raises anew precisely the problem which the opposition of phenomena or noumena was intended to solve. Phenomena are related to noumena as the trees to the wood, not as a compound to its atoms. The solution of the difficulty is thus only to be found in the type of consciousness which contains both--and this, Hegel says, is self-consciousness.
Consciousness has found "seeing" and "hearing", etc., pass away in the dialectic process of sense-experience.
Hegel describes empiricism from what would become the postmodern view of it in his Phenomenology and his Logic. From the Logic:
The rise of Empiricism is due to the need thus stated of concrete contents, and a firm footing - needs which the abstract metaphysic of the understanding failed to satisfy. Now by concreteness of contents it is meant that we must know the objects of consciousness as intrinsically determinate and as the unity of distinct characteristics. But, as we have already seen, this is by no means the case with the metaphysic of understanding, if it conform to its principle. With the mere understanding, thinking is limited to the form of an abstract universal, and can never advance to the particularisation of this universal. Thus we find the metaphysicians engaged in an attempt to elicit by the instrumentality of thought what was the essence or fundamental attribute of the Soul. The Soul, they said, is simple. The simplicity thus ascribed to the Soul meant a mere and utter simplicity, from which difference is excluded: difference, or in other words composition, being made the fundamental attribute of body, or of matter in general. Clearly, in simplicity of this narrow type we have a very shallow category, quite incapable of embracing the wealth of the soul or of the mind. When it thus appeared that abstract metaphysical thinking was inadequate, it was felt that resource must be had to empirical psychology. The same happened in the case of Rational Physics. The current phrases there were, for instance, that space is infinite, that Nature makes no leap, etc. Evidently this phraseology was wholly unsatisfactory in presence of the plenitude and life of nature.”
Bertrand Russell (1911) says in The Philosophical Importance of Mathematical Logic that:
“In spite of the fact that traditional empiricism is mistaken in its theory of knowledge, it must not be supposed that idealism is right. Idealism at least every theory of knowledge which is derived from Kant-assumes that the universality of a priori truths comes from their property of expressing properties of the mind: I things appear to be thus because the nature of the appearance depends on the subject in the same way that, if we have blue spectacles, everything appears to be blue. The categories of Kant are the coloured spectacles of the mind; truths a priori are the false appearances produced by those spectacles. Besides, we must know that everybody has spectacles of the same kind and that the colour of the spectacles never changes. Kant did not deign to tell us how he knew this.”
John Dewey says:
Since the impressions made upon the mind by objects were generally termed sensations, empiricism thus became a doctrine of sensationalism -- that is to say, a doctrine which identified knowledge with the reception and association of sensory impressions. In John Locke, the most influential of the empiricists, we find this sensationalism mitigated by a recognition of certain mental faculties, like discernment or discrimination, comparison, abstraction, and generalization which work up the material of sense into definite and organized forms and which even evolve new ideas on their own account, such as the fundamental conceptions of morals and mathematics. (See ante, p. 61.) But some of his successors, especially in France in the latter part of the eighteenth century, carried his doctrine to the limit; they regarded discernment and judgment as peculiar sensations made in us by the conjoint presence of other sensations. Locke had held that the mind is a blank piece of paper, or a wax tablet with nothing engraved on it at birth (a tabula rasa) so far as any contents of ideas were concerned, but had endowed it with activities to be exercised upon the material received. His French successors razed away the powers and derived them also from impressions received.